Central Statistical Office in Poland

Demographic Surveys and Labour Market Department

Al. Niepodleglosci 208, 00-925 Warszawa

Not available.

ISCO-08, NACE Rev. 2, etc.

Usual residence means the place where a person normally spends the daily period of rest, regardless of temporary absences for purposes of recreation, holidays, visits to friends and relatives, business, medical treatment or religious pilgrimage.
Persons usually resident in the place of enumeration but absent, or expected to be absent, at the time of the census for less than one year shall be considered as temporarily absent persons and thus included in the total unsually population. In contrast, persons living or expected to live outside the place of enumeration for one year or more shall not be considered temporarily absent and shall therefore be excluded from the total population. This is regardless of the length of visits that they may pay to their families from time to time.
Persons who are enumerated but do not meet the criteria for usual residence in the place of enumeration, i.e. do not live or do not expect to live in the place of enumeration for a continuous period of at least 12 months, are considered temporarily present and are therefore not counted in the total usually resident population.

Male, Female

The age reached at the reference date (in completed years).

Marital status is the (legal) conjugal status of an individual in relation to the marriage laws of the country (de jure status).
A person shall be classified according to his/her most recently acquired legal marital status at the reference date.
'Registered partnerships' are reported only by countries that have a legal framework regulating partnerships that:
(a) lead to legal conjugal obligations between two persons;
(b) are not marriages;
(c) prevent persons to commit themselves into multiple partnerships with different partners.
In countries where the legislation includes provisions for married partners to be 'legally separated', such 'legally separated' persons are classified under 'married'.

In 2011 Polish Census the legal position regarding marital status for persons aged 15 years and more was defined as marital status pursuant to the law in force in Poland (the list of legal acts below).  Polish law allows marriages for women aged 16 and more and for men aged 18 and more.
Polish legislation does not provide for same-sex marriages. As a result, no information was prepared in the Polish census on same-sex relationships, either for legal civil status or for de facto marital status.
Polish legislation does not provide for registered partnerships. Partnerships were determined on the basis of de facto marital status, As a result, no information was prepared in the Polish census regarding partners in registered partnerships.
A legal marital status refers to marriages contracted according to lawful rules at the civil status Office — the Law on Civil Status Acts from September 29, 1986 (Journal of Laws 1986 No. 36, item 180) with later amendments.
A marriage is concluded when a man and a woman are both present before the head of registry office and make a statement that they take each other in marital union. The head of register office draws up a marriage certificate.
Since 1999 — according to the Act from July 24, 1998 — the Family and Tutelary Code, the Civil Proceedings Code, the Law on Civil Status Acts, the Act on Relation of the State to the Catholic Church in the Republic of Poland and the other selected acts (Journal of Laws No. 117, item 757) — in the local civil status offices in Poland are registered all marriages, including those based on the internal law of the Churches or the Religious Associations. Marriages contracted on the basis of canonic law subordinate the civil Polish laws and result in the same civil and law consequences as marriages contracted in the local civil status offices.
The following churches and religious associations can conduct valid concordat marriages:

1. The Catholic Church, including the Roman Catholic, Greek Orthodox, Uniate and Neo-Uniate and Armenian Churches,

2. The Polish Autocephalous Orthodox Church,

3. The Lutheran Church,

4. The Reformed Church,

5. The Evangelical Methodist Church in Poland,

6. The Baptist Church,

7. The Seventh Day Adventist Church,

8. The Mariavite Church,

9. The Pentecostal Church,

10. The Polish Catholic Church,

11. The Union of Jewish Communities.

Divorces as a legal institution were introduced in Poland on January 1, 1946 on the basis of the Act from September 25, 1945 — Marriage Law (Journal of Laws 1945 No. 48, item 270).  According to Polish law, the court pronounces the divorce at the request of one or both spouses.
Separations as a legal institution were introduced in Poland on December 15, 1999 on the basis of the Act from May 21, 1999 — change of Family and Tutelary Code, Civil Code, Civil Procedure Code and other acts (Journal of Laws 1999 No. 52, item 532)
The formal separation is a legal  institution, which is adjudicated by a  regional family court at the request of one or both spouses. The judicial decree of separation in principle has the same effects as a divorce, unless otherwise provided by statute. The most significant difference is that a separated person is not allowed to remarry.
The rules of the family law are regulated by the Act from February 25, 1964 — Family and Tutelary Code (Journal of Laws 1964 No. 9, item 59) with later amendments.

The family nucleus is defined in the narrow sense, that is as two or more persons who belong to the same household and who are related as husband and wife, as partners in a registered partnership, as partners in a consensual union, or as parent and child. Thus a family comprises a couple without children, or a couple with one or more children, or a lone parent with one or more children. This family concept limits relationships between children and adults to direct (first-degree) relationships, that is between parents and children.
Child (son/daughter) refers to a blood, step- or adopted son or daughter (regardless of age or marital status) who has usual residence in the household of at least one of the parents, and who has no partner or own children in the same household. Foster children are not included. A son or daughter who lives with a spouse, with a registered partner, with a partner in a consensual union, or with one or more own children, is not considered to be a child. A child who alternates between two households (for instance if his or her parents are divorced) shall consider the one where he or she spends the majority of the time as his or her household. Where an equal amount of time is spent with both parents the household shall be the one where the child is found at the time on census night.
The term couple shall include married couples, couples in registered partnerships, and couples who live in a consensual union.
Registered partnerships are reported only by countries that have a legal framework regulating partnerships that:
(a) lead to legal conjugal obligations between two persons;
(b) are not marriages;
(c) prevent persons to commit themselves into multiple partnerships with different partners.
Two persons are considered to be partners in a 'consensual union' when they
— belong to the same household, and
— have a marriage-like relationship with each other, and
— are not married to or in a registered partnership with each other.
'Skip-generation households' (households consisting of a grandparent or grandparents and one or more grandchildren, but no parent of those grandchildren) are not included in the definition of a family.

Private households may be defined according to the 'housekeeping concept' , or, if this is not possible, Member States may apply the 'household-dwelling' concept.
1. Housekeeping concept
According to the housekeeping concept, a private household is either:
(a) A one-person household, that is a person who lives alone in a separate housing unit or who occupies, as a lodger, a separate room (or rooms) of a housing unit but does not join with any of the other occupants of the housing unit to form part of a multiperson household as defined below; or
(b) A multiperson household, that is a group of two or more persons who combine to occupy the whole or part of a housing unit and to provide themselves with food and possibly other essentials for living. Members of the group may pool their incomes to a greater or lesser extent.
2. Household-dwelling concept
The household-dwelling concept considers all persons living in a housing unit to be members of the same household, such that there is one household per occupied housing unit. In the household dwelling concept, then, the number of occupied housing units and the number of households occupying them is equal, and the locations of the housing units and house­ holds are identical.
The category 'Persons living in a private household' comprises 'Persons in a family nucleus' and 'Persons not in a family nucleus'. The category 'Persons in a family nucleus' comprises all persons who belong to a private household that contains a family nucleus of which they are a member. 'Persons not in a family nucleus' comprises all persons who either belong to a non-family household or to a family household without being member of any family nucleus in that household.
A non-family household can be a one-person household ('Living alone') or a multiperson household without any family nucleus. The category 'Not living alone' comprises persons that live either in a multiperson household without any family nucleus or in a family household without being member of any family nucleus in that household. Persons who belong to a skip-generation household and who are not member of any family nucleus in that household shall be classified in the optional category 'Persons living in a household with relative(s)'.
The term 'son/daughter' is defined as the term 'child' in the technical specifications for the topic 'Family status'. 'Husband/wife couple' means a married opposite-sex couple.
'Registered partnership' is defined as in the technical specifications for the topic 'Legal marital status'. 'Consensual union' is defined as in the technical specifications for the topic 'Family status'.
The category 'Partners' comprises 'Persons in a married couple', 'Partners in a registered partnership' and 'Partners in a consensual union'.
'Primary homeless persons' are persons living in the streets without a shelter that would fall within the scope of living quarters as defined in the technical specifications for the topic 'Type of living quarters'.

 In 2011 Polish Census the private households were separated according to the economic definition ie. using the housekeeping concept.
In the process of data collection in this area, it was particularly important to indicate for each person residing in the dwelling the number of household, whose person was a member.
In each private household the reference person has been indicated, and  then the relationships of all  other household members to the  reference person were established.

The following classification was used:

1. Reference person
2. Husband/ male partner or wife /female partner in a formal marriage or in a consensual union with reference person, living together in a dwelling
3. Natural or adopted child of the reference person and stepson (ie. child of spouse of reference person), regardless of age and marital status of a child
4. Father or mother of reference person, and the stepfather and stepmother of reference person
5. Father-in-law and mother-in-law ie. parents of spouse of reference person,
6. Daughter-in-law and son-in-law of reference person - the spouse of a child,
7. Siblings of reference person, regardless of age and marital status of these persons,
8. Grandparents and great-grandparents of reference person and spouse of reference person,
9. Grandchildren and great-grandchildren of reference person and spouse of reference person, and spouses of grandchildren,
10. Other relatives: spouses of siblings and their children, spouses of siblings of reference person and his or her spouse (daughter-in-law, brother in law), other relatives of reference person or spouse of reference person (uncle, aunt, etc..)
11. Persons unrelated of reference person: children, parents, siblings and other relatives of partners of reference person, partners of relatives of reference person (ie. partners of the symbols 3-11) and the other persons.

 For persons in marriage or in consensual union, the  spouse / partner, with whom persons formed a common household, was indicated.
The parents (father and mother) were indicated for each person who was a child of one of the persons residing  in the same dwelling and forming a common household. It was regardless of  age and marital status of this child.
The relationship with the parents of children residing in the foster families was not indicated, regardless of whether such persons were related to the child or not.
Families were separated on the basis of each person's relationship with the reference person  and additional information: legal marital status, date of marriage or the creation of an informal relationship, a number of parents and number of spouse / partner.
The resulting data on households and families have been developed only for persons residing in dwellings which were drawn for a sample survey.
Homeless persons (roofless) were not taken into account to establish the structure of households and families and types thereof.

Current activity status' is the current relationship of a person to economic activity, based on a reference period of one week, which may be either a specified, recent, fixed, calendar week, or the last complete calendar week, or the last seven days prior to enumeration.
The 'currently economically active population' comprises all persons who fulfil the requirements for inclusion among the employed or the unemployed.
'Employed' persons comprise all persons aged 15 years or over who during the reference week:
(a) performed at least one hour of work for pay or profit, in cash or in kind, or
(b) were temporarily absent from a job in which they had already worked and to which they maintained a formal attachment, or from a self-employment activity.
The 'unemployed' comprise all persons aged 15 years or over who were:
(a) 'without work', that is, were not in wage employment or self-employment during the reference week; and
(b) 'currently available for work', that is, were available for wage employment or self-employment during the reference week and for two weeks after that; and
(c) 'seeking work', that is, had taken specific steps to seek wage employment or self-employment within four weeks ending with the reference week.
The category 'Currently not economically active' includes persons below the national minimum age for economic activity.
In ascribing a single activity status to each person, priority is given to the status of 'employed' in preference to 'unemployed', and to the status of 'unemployed' in preference to 'not economically active'.

Occupation' refers to the type of work done in a job (that is the main tasks and duties of the work). Persons doing more than one job are allocated an occupation based on their main job, which is identified according to the time spent on the job or, if not available, to the income received.
The breakdown by occupation is available for persons aged 15 or over that were:
— employed during the reference week, or
— unemployed during the reference week, but have ever been in employment
Persons are classified according to the occupation they had during their most recent employment. The categories included in the breakdown 'occupation' correspond to the major groups of the ISCO-08 (COM) classification.
Persons under the age of 15 years, as well as persons aged 15 or over that were:
— not economically active during the reference week, or
— unemployed, never worked before (i.e. they have never been employed in their lives)
are classified under 'not applicable'.
The allocation of a person within the breakdowns of the topics 'Occupation', 'Industry' and 'Status in employment' is based on the same job.

Industry (branch of economic activity) is the kind of production or activity of the establishment (or similar unit) in which the job of a currently economically active person is located.
Persons doing more than one job shall be allocated an industry (branch of economic activity) based on their main job, which is to be identified according to the time spent on the job or (if not available) the income received.
The breakdown by industry is available for persons aged 15 or over that were:
— employed during the reference week, or
— unemployed during the reference week, but have ever been in employment
Persons are classified according to the industry they worked in during their most recent employment. The categories included in the breakdown 'industry' list the 21 sections of the NACE Rev. 2 classification and appropriate aggregates.
Persons under the age of 15 years, as well as persons aged 15 or over that were:
— not economically active during the reference week, or
— unemployed, and have never worked before (i.e. have never been employed in their lives)
are classified under 'not applicable'.
The allocation of a person within the breakdowns of the topics 'Occupation', 'Industry' and 'Status in employment' is based on the same job.

An 'employee' is a person who works in a 'paid employment' job, that is a job where the explicit or implicit contract of employment gives the incumbent a basic remuneration, which is independent of the revenue of the unit for which he/she works.
An 'employer' is a person who, working on his or her own account or with a small number of partners, holds a 'self-employment' job and, in this capacity, on a continuous basis (including the reference week) has engaged one or more persons to work for him/her as 'employees'.
If a person is both employer and employee, he/she shall be allocated to only one group according to the time spent on the job or (if not available) the income received.
An 'own-account worker' is a person who, working on his/her own account or with one or a few partners, holds a 'self-employment job' and has not engaged, on a continuous basis (including the reference week), any 'employees'.
A 'contributing family worker' is a person who
— holds a 'self-employment’ job in a market-oriented establishment operated by a related person, living in the same household, and
— cannot be regarded as a partner (that is an employer or own-account worker) because the degree of commitment to the operation of the establishment, in terms of working time or other factors to be determined by national circumstances, is not at a level comparable to that of the head of the establishment.
A 'member of a producers' cooperative' is a person who holds a 'self-employment' job in an establishment organised as a coop­ erative, in which each member takes part on an equal footing with other members in determining the organisation of production, sales and/or other work, the investments and the distribution of the proceeds among the members.

The location of the place of work is the geographical area in which a currently employed person does his/her job.
The place of work of those mostly working at home is the same as their usual residence. The term 'working' refers to work done as an 'employed person' as defined under the topic 'Current activity status'. 'Mostly' working at home means that the person spends all or most of the time working at home, and less, or no, time in a place of work other than at home.

'Educational attainment' refers to the highest level successfully completed in the educational system of the country where the education was received. All education which is relevant to the completion of a level is taken into account even if this was provided outside schools and universities.
Persons aged 15 years or over are classified under only one of the categories according to their educational attainment (highest completed level). Persons under the age of 15 years are classified under 'not applicable'.

A locality is defined as a distinct population cluster, that is an area defined by population living in neighbouring or contiguous buildings. Such buildings may either:
(a) form a continuous built-up area with a clearly recognisable street formation; or
(b) though not part of such a built-up area, comprise a group of buildings to which a locally recognised place name is uniquely attached; or
(c) though not meeting either of the above two criteria, constitute a group of buildings, none of which is separated from its nearest neighbour by more than 200 metres.

Place of birth is defined as the place of usual residence of the mother at the time of the birth, or, if not available, as the place in which the birth took place.
Information on the country of birth is based on the international boundaries existing on 1 January 2011. 'EU Member State', in particular, means a country that is a member of the European Union on 1 January 2011. The list of countries in the breakdown 'country/place of birth' serves only for statistical purposes.
For reporting countries that are EU Member States, the sub-category under the category 'other EU Member State' that refers to their Member State does not apply. For reporting countries that are not EU Member States, the category 'Other EU Member State' shall be read as 'EU Member State'.
The category 'Information not classifiable according to current borders' covers those persons whose country of birth existed at the time of the birth, but no longer exists at the time of the census, and who cannot be allocated uniquely to one country existing at the time of the census, i.e. according to current borders.
The category 'outside any country' covers persons for whom the usual residence of the mother at the time of the birth is not known and who where born outside the borders of any country, for example at sea or in the air.

Citizenship is defined as the particular legal bond between an individual and his/her State, acquired by birth or naturalisation, whether by declaration, option, marriage or other means according to the national legislation.
A person with two or more citizenships is allocated to only one country of citizenship, to be determined in the following order of precedence:
1. reporting country; or
2. if the person does not have the citizenship of the reporting country: other EU Member State; 3. if the person does not have the citizenship of another EU Member State: other country outside the European Union.
'EU Member State' means a country that is a member of the European Union on 1 January 2011. The list of countries in the breakdown 'Country of citizenship' shall only apply for statistical purposes.
For reporting countries that are EU Member States, the sub-category of the category 'citizenship not of reporting country, but other EU Member State' that refers to their Member State does not apply. For reporting countries that are not EU Member States, the category 'citizenship not of reporting country, but other EU Member State' shall be changed to 'citizenship of an EU Member State'.
Persons who are neither citizens of any country nor stateless and who have some but not all of the rights and duties associated with citizenship shall be classified under 'recognised non-citizens'.

The year of arrival is the calendar year in which a person most recently established usual residence in the country. The data for 2011 refer to the time span between 1 January 2011 and the reference date.

This indicates the relationship between the current place of usual residence and the place of usual residence one year prior to the census. Children under one year of age are classified under 'Not applicable'.
For all persons that have changed their usual residence more than once within the year prior to the reference date, the previous place of usual residence is the last usual residence from which they moved to their current place of usual residence.

The topic 'Housing arrangements' covers the whole population and refers to the type of housing in which a person usually resides at the time of the census. This covers all persons who are usual residents in different types of living quarters, or who do not have a usual residence and stay temporarily in some type of living quarters, or who are roofless, sleeping rough or in emergency shelters, when the census is taken.
Occupants are persons with their usual residence in the places listed in the respective category.
'Conventional dwellings' are structurally separate and independent premises at fixed locations which are designed for permanent human habitation and are, at the reference date, either used as a residence, or vacant, or reserved for seasonal or secondary use.
'Separate' means surrounded by walls and covered by a roof or ceiling so that one or more persons can isolate themselves. 'Independent' means having direct access from a street or a staircase, passage, gallery or grounds.
'Other housing units' are huts, cabins, shacks, shanties, caravans, houseboats, barns, mills, caves or any other shelter used for human habitation at the time of the census, irrespective if it was designed for human habitation.
'Collective living quarters' are premises which are designed for habitation by large groups of individuals or several households and which are used as the usual residence of at least one person at the time of the census.
'Occupied conventional dwellings', 'other housing units' and 'collective living quarters' together represent'‘living quarters'. Any 'living quarter' must be the usual residence of at least one person.
The sum of occupied conventional dwellings and other housing units represents 'housing units'.
The homeless (persons who are not usual residents in any living quarter category) can be persons living in the streets without a shelter that would fall within the scope of living quarters (primary homelessness) or persons moving frequently between temporary accommodation (secondary homelessness).

The family nucleus is defined in the narrow sense, that is as two or more persons who belong to the same household and who are related as husband and wife, as partners in a registered partnership, as partners in a consensual union, or as parent and child. Thus a family comprises a couple without children, or a couple with one or more children, or a lone parent with one or more children. This family concept limits relationships between children and adults to direct (first-degree) relationships, that is between parents and children.
Child (son/daughter) refers to a blood, step- or adopted son or daughter (regardless of age or marital status) who has usual residence in the household of at least one of the parents, and who has no partner or own children in the same household. Foster children are not included. A son or daughter who lives with a spouse, with a registered partner, with a partner in a consensual union, or with one or more own children, is not considered to be a child. A child who alternates between two households (for instance if his or her parents are divorced) shall consider the one where he or she spends the majority of the time as his or her household. Where an equal amount of time is spent with both parents the household shall be the one where the child is found at the time on census night.
The term couple shall include married couples, couples in registered partnerships, and couples who live in a consensual union.
Registered partnerships are reported only by countries that have a legal framework regulating partnerships that:
(a) lead to legal conjugal obligations between two persons;
(b) are not marriages;
(c) prevent persons to commit themselves into multiple partnerships with different partners.
Two persons are considered to be partners in a 'consensual union' when they
— belong to the same household, and
— have a marriage-like relationship with each other, and
— are not married to or in a registered partnership with each other.
'Skip-generation households' (households consisting of a grandparent or grandparents and one or more grandchildren, but no parent of those grandchildren) are not included in the definition of a family.

The family nucleus is defined in the narrow sense, that is as two or more persons who belong to the same household and who are related as husband and wife, as partners in a registered partnership, as partners in a consensual union, or as parent and child. Thus a family comprises a couple without children, or a couple with one or more children, or a lone parent with one or more children. This family concept limits relationships between children and adults to direct (first-degree) relationships, that is between parents and children.
Child (son/daughter) refers to a blood, step- or adopted son or daughter (regardless of age or marital status) who has usual residence in the household of at least one of the parents, and who has no partner or own children in the same household. Foster children are not included. A son or daughter who lives with a spouse, with a registered partner, with a partner in a consensual union, or with one or more own children, is not considered to be a child. A child who alternates between two households (for instance if his or her parents are divorced) shall consider the one where he or she spends the majority of the time as his or her household. Where an equal amount of time is spent with both parents the household shall be the one where the child is found at the time on census night.
The term couple shall include married couples, couples in registered partnerships, and couples who live in a consensual union.
Registered partnerships are reported only by countries that have a legal framework regulating partnerships that:
(a) lead to legal conjugal obligations between two persons;
(b) are not marriages;
(c) prevent persons to commit themselves into multiple partnerships with different partners.
Two persons are considered to be partners in a 'consensual union' when they
— belong to the same household, and
— have a marriage-like relationship with each other, and
— are not married to or in a registered partnership with each other.
'Skip-generation households' (households consisting of a grandparent or grandparents and one or more grandchildren, but no parent of those grandchildren) are not included in the definition of a family.

Private households may be defined according to the 'housekeeping concept' , or, if this is not possible, Member States may apply the 'household-dwelling' concept.
1. Housekeeping concept
According to the housekeeping concept, a private household is either:
(a) A one-person household, that is a person who lives alone in a separate housing unit or who occupies, as a lodger, a separate room (or rooms) of a housing unit but does not join with any of the other occupants of the housing unit to form part of a multiperson household as defined below; or
(b) A multiperson household, that is a group of two or more persons who combine to occupy the whole or part of a housing unit and to provide themselves with food and possibly other essentials for living. Members of the group may pool their incomes to a greater or lesser extent.
2. Household-dwelling concept
The household-dwelling concept considers all persons living in a housing unit to be members of the same household, such that there is one household per occupied housing unit. In the household dwelling concept, then, the number of occupied housing units and the number of households occupying them is equal, and the locations of the housing units and house­ holds are identical.
The category 'Persons living in a private household' comprises 'Persons in a family nucleus' and 'Persons not in a family nucleus'. The category 'Persons in a family nucleus' comprises all persons who belong to a private household that contains a family nucleus of which they are a member. 'Persons not in a family nucleus' comprises all persons who either belong to a non-family household or to a family household without being member of any family nucleus in that household.
A non-family household can be a one-person household ('Living alone') or a multiperson household without any family nucleus. The category 'Not living alone' comprises persons that live either in a multiperson household without any family nucleus or in a family household without being member of any family nucleus in that household. Persons who belong to a skip-generation household and who are not member of any family nucleus in that household shall be classified in the optional category 'Persons living in a household with relative(s)'.
The term 'son/daughter' is defined as the term 'child' in the technical specifications for the topic 'Family status'. 'Husband/wife couple' means a married opposite-sex couple.
'Registered partnership' is defined as in the technical specifications for the topic 'Legal marital status'. 'Consensual union' is defined as in the technical specifications for the topic 'Family status'.
The category 'Partners' comprises 'Persons in a married couple', 'Partners in a registered partnership' and 'Partners in a consensual union'.
'Primary homeless persons' are persons living in the streets without a shelter that would fall within the scope of living quarters as defined in the technical specifications for the topic 'Type of living quarters'.

Private households may be defined according to the 'housekeeping concept' , or, if this is not possible, Member States may apply the 'household-dwelling' concept.
1. Housekeeping concept
According to the housekeeping concept, a private household is either:
(a) A one-person household, that is a person who lives alone in a separate housing unit or who occupies, as a lodger, a separate room (or rooms) of a housing unit but does not join with any of the other occupants of the housing unit to form part of a multiperson household as defined below; or
(b) A multiperson household, that is a group of two or more persons who combine to occupy the whole or part of a housing unit and to provide themselves with food and possibly other essentials for living. Members of the group may pool their incomes to a greater or lesser extent.
2. Household-dwelling concept
The household-dwelling concept considers all persons living in a housing unit to be members of the same household, such that there is one household per occupied housing unit. In the household dwelling concept, then, the number of occupied housing units and the number of households occupying them is equal, and the locations of the housing units and house­ holds are identical.
The category 'Persons living in a private household' comprises 'Persons in a family nucleus' and 'Persons not in a family nucleus'. The category 'Persons in a family nucleus' comprises all persons who belong to a private household that contains a family nucleus of which they are a member. 'Persons not in a family nucleus' comprises all persons who either belong to a non-family household or to a family household without being member of any family nucleus in that household.
A non-family household can be a one-person household ('Living alone') or a multiperson household without any family nucleus. The category 'Not living alone' comprises persons that live either in a multiperson household without any family nucleus or in a family household without being member of any family nucleus in that household. Persons who belong to a skip-generation household and who are not member of any family nucleus in that household shall be classified in the optional category 'Persons living in a household with relative(s)'.
The term 'son/daughter' is defined as the term 'child' in the technical specifications for the topic 'Family status'. 'Husband/wife couple' means a married opposite-sex couple.
'Registered partnership' is defined as in the technical specifications for the topic 'Legal marital status'. 'Consensual union' is defined as in the technical specifications for the topic 'Family status'.
The category 'Partners' comprises 'Persons in a married couple', 'Partners in a registered partnership' and 'Partners in a consensual union'.
'Primary homeless persons' are persons living in the streets without a shelter that would fall within the scope of living quarters as defined in the technical specifications for the topic 'Type of living quarters'.

The topic 'Tenure status of households' refers to the arrangements under which a private household occupies all or part of a housing unit.
Households that are in the process of paying off a mortgage on the housing unit in which they live or purchasing their housing unit over time under other financial arrangementsare classified under 'Households of which at least one member is the owner of the housing unit'.
Households of which at least one member is the owner of the housing unit and at least one member tenant of all or part of the housing unit are classified under category 'Households of which at least one member is the owner of the housing unit'.

'Conventional dwellings' are structurally separate and independent premises at fixed locations which are designed for permanent human habitation and are, at the reference date, either used as a residence, or vacant, or reserved for seasonal or secondary use.
'Separate' means surrounded by walls and covered by a roof or ceiling so that one or more persons can isolate themselves. 'Independent' means having direct access from a street or a staircase, passage, gallery or grounds.
'Other housing units' are huts, cabins, shacks, shanties, caravans, houseboats, barns, mills, caves or any other shelter used for human habitation at the time of the census, irrespective if it was designed for human habitation.
'Collective living quarters' are premises which are designed for habitation by large groups of individuals or several households and which are used as the usual residence of at least one person at the time of the census.
'Occupied conventional dwellings', 'other housing units' and 'collective living quarters' together represent'‘living quarters'. Any 'living quarter' must be the usual residence of at least one person.

'Occupied conventional dwellings' are conventional dwellings which are the usual residence of one or more persons at the time of the census. 'Unoccupied conventional dwellings' are conventional dwellings which are not the usual residence of any person at the time of the census.
Conventional dwellings with persons present but not included in the census are classified under the category 'Dwellings reserved for seasonal or secondary use'.

The topic 'Type of ownership' refers to the ownership of the dwelling and not to that of the land on which the dwelling stands.
'Owner-occupied dwellings' are those where at least one occupant of the dwelling owns parts or the whole of the dwelling. 'Cooperative ownership' refers to ownership within the framework of a housing cooperative.
'Rented dwellings' are those where at least one occupant pays a rent for the occupation of the dwelling, and where no occupant owns parts or the whole of the dwelling.

The number of occupants of a housing unit is the number of people for whom the housing unit is the usual residence.

Useful floor space is defined as the floor space measured inside the outer walls excluding non-habitable cellars and attics and, in multi-dwelling buildings, all common spaces; or the total floor space of rooms falling under the concept of 'room'.
A 'room' is defined as a space in a housing unit enclosed by walls reaching from the floor to the ceiling or roof, of a size large enough to hold a bed for an adult (4 square metres at least) and at least 2 metres high over the major area of the ceiling.

A 'room' is defined as a space in a housing unit enclosed by walls reaching from the floor to the ceiling or roof, of a size large enough to hold a bed for an adult (4 square metres at least) and at least 2 metres high over the major area of the ceiling.

The topic ‘Density standard’ relates the useful floor space in square metres or the number of rooms to the number of occupants, as specified under the topic 'Number of occupants'.
Data report on the density standard measured by the 'useful floor space', or, if not possible, by the 'number of rooms'.

The topic ‘Density standard’ relates the useful floor space in square metres or the number of rooms to the number of occupants, as specified under the topic 'Number of occupants'.
Data report on the density standard measured by the 'useful floor space', or, if not possible, by the 'number of rooms'.

A housing unit considered as having  a piped water installation is a unit inside which there is a tap with running water. The installation is classified as follows:  connected to a network (water supply network) or to a local water supply system.

A housing unit considered as having a flush toilet is a housing unit within which there is an installation which is flushed by water from a flushing cistern,  connected to a water supply system. This installation may be located either in a separate room (WC), or in a bathroom.
Information is broken down by type of installation discharging waste from a building: either to the sewage network, or to a local sewage system.

A bathing facility is any facility designed to wash the whole body and includes shower facilities.

A housing unit is considered as centrally heated if heating is provided either from a community heating centre or from an installation built in the building or in the housing unit, established for heating purposes, without regard to the source of energy.

The topic 'Dwellings by type of building' refers to the number of dwellings in the building in which the dwelling is placed.

The topic 'Dwellings by period of construction' refers to the year when the building in which the dwelling is placed was completed.

The EU programme for the 2011 population and housing censuses include data on persons, private households, family nuclei, conventional dwellings and living quarters

Persons enumerated in the 2011 census are those who were usually resident in the territory of the reporting country at the census reference date. Usual residence means the place where a person normally spends the daily period of rest, regardless of temporary absences for purposes of recreation, holidays, visits to friends and relatives, business, medical treatment or religious pilgrimage

Data are available at different levels of geographical detail: national, NUTS2, NUTS3 and local administrative units (LAU2)

Data refer to the situation in the reporting country at the census reference date (see item 5)

Counts of statistical units

The legal basis for work related to the preparation, implementation, and analysis of results of the Population and Housing Census was the Act of 4 March 2010 on the National Census of Population and Housing in 2011 (Journal of Laws of 2010, No 47, item 277, as amended), hereinafter referred to as the "NSP 2011 Act". The Act of 29 June 1995 on Public Statistics[1] and the Act of 6 September 2001 on Access to Public Information[2]also had a considerable impact on the performance of the census.
At the stage of legislative work, the draft  Act on the National Census of Population and Housing in 2011  (NSP 2011 Act) was assessed by the competent authority, i.e. by the Minister of Foreign Affairs, as being in compliance with European Union law, including, first of all, Regulation (EC) No 763/2008 of the European Parliament and of the Council on population and housing censuses.
In accordance with the NSP 2011 Act, it was decided that data sources include data from administrative registers, data from sample  surveys, and  data from traditional censuses.
The Population and Housing Census  2011 Act contains provisions setting out data sources and the scope of information to be collected during the census, as well as procedures governing data gathering. On the basis of this Act, data were obtained from natural persons, and were also submitted by entities managing information systems. A detailed list of topics and data to be collected during the census exclusively for the national needs, the list of entities required to submit data to the President of the Central Statistical Office in the course of census activities, as well as the detailed scope of these data and deadlines within which they were to be submitted were clearly set out in the annexes to the Act in question. Information collected during the census was gathered primarily from available administrative sources and used to prepare and update the sampling frame for addresses/housing units register, to carry our random sampling in the  sample survey, and also as a direct source of census data. Therefore, a clear and detailed legal basis for actions undertaken was essential.
Data which cannot be found in public administration information systems, or data which do not meet quality requirements for public statistics, were collected from persons covered by the census. However, in such cases state-of-the-art techniques were used for the collection of data in order to eliminate paper forms. This approach aimed at reducing the costs of the census and to alleviating burdens on persons covered by the census, while retaining high quality of the results of the census.
Entities and persons covered by the NSP 2011 Act:

1) persons usually resident or  temporarily staying in housing units, buildings, structures
and premises which are not housing units, and homeless persons,

2) housing units and buildings with housing units, as well as occupied collective living quarters and other occupied premises which are not housing units.

The procedure of gathering data listed in the NSP 2011 Act was implemented using a mixed method, i.e. combining the use of information systems of public administration and data gathered through a full – scope survey and sample survey, in the following sequence:

- extracting data from information systems;

-  an Internet-based self-enumeration, consisting of accepting or correcting within a specific time-frame  data obtained from information systems;

- a telephone interview conducted by a statistical interviewer, assisted with computer software(CATI);

- an interview conducted by census  enumerator recordered on a hand-held device (CAPI).

Applicable principles governing the gathering and processing of data under the NSP 2011 Act are in compliance with regulatory provisions adopted in other acts, i.e. in the Act of 29 June 1995 on Public Statistics and in the Act of 29 August 1998 on Personal Data Protection (Article 10 and Article 11 of the NSP 2011 Act). In its regulatory provisions regarding the gathering and processing of data this Act clearly and explicitly guaranteed special protection of such data. That is to say, all data collected and stored during the census are confidential and enjoy special protection on the basis of the secrecy of statistics (according to the principles set out in the Act on Public Statistics). Moreover, these data are processed in accordance with the Act on the Protection of Personal Data.
The Act on Public Statistics determines in what cases personal data may be obtained and from whom, as well as what level of a legal act is required in determining obligations in these respects. The provisions of that Act indicate the manner in which it is possible to collect statistical data, to be used in public statistics, from all available sources set out in detail in the public statistical surveys programme, and to store statistical data obtained from business entities and about these entities and their operations, as well as to collect and store statistical data obtained from natural persons concerning these persons, their living, and their situation.
The provisions of the Act on Public Statistics determine the basic principle of protection of personal data collected to be used in public statistics. In accordance with that Article, individual and personal data collected during public statistics surveys are confidential and enjoy special protection; these data may only be used for the purposes of studies, preparation of data sheets, and statistical analysis. They can also be used by public statistics services for the preparation of the sampling frame for statistical surveys conducted by these services. Making individual and personal data available or using them for purposes other than those indicated above is prohibited (statistical secrecy). The principle of statistical secrecy provided for in the Act, covering all individual and personal data in a manner which does not envisage any exceptions or derogations, refers directly to the NSP 2011 Act.
The provisions of the Act on the Protection of Personal Data do not restrict the access to personal data collected for statistical purposes to persons who are the subject of such data, or to public administration information systems. This is confirmed by the provisions of the above-mentioned Act where in Article 2(3) and Article 26(2)(1) the legislator explicitly permits the processing of data for statistical surveys. These provisions are equivalent to permitting data administrators to make data available for public statistics purposes.
As regards the processing of so-called sensitive data, in Article 27(2)(2) the legislator allows for a possibility of processing such data, provided that a specific provision of another act permits the processing of such data without the agreement of the person concerned, and provides full guarantee of protection of such data. In the light of Article 10 of the Act on Public Statistics it can be stated that the above-mentioned provision, by providing statistical secrecy for collected data, indisputably gives such guarantees. The NSP 2011 Act takes into account the above-mentioned provisions of the Act on Public Statistics and of the Act on the Protection of Personal Data.
The NSP 2011 Act also determined legal bases for the organisation of census work. In accordance with this Act, the following persons are in charge of the work regarding the preparation and performance of the census, as well as for the processing of the results of the census and for making them available:

- the President of the Central Statistical Office, as the General Census Commissioner;

- Voivodship Governors (Voivods)  as Voivodship Census Commissioners;

- Commune Heads (Mayors, Presidents of Town Councils) - as Gmina Census Commissioners.

The Central Census Office and the Methodology and Analyses Team were created, working with the President  of the Central Statistical Office. In the  voivodship and  gminas, Voivodship (WBS) and Gmina (GBS) Census Offices were established. Their tasks were laid down in the NSP 2011 Act. Voivodship and Gmina Census Offices had their tasks and work timetables precisely defined. They were established to operate for the time necessary to carry out census-related work only.
In order to efficiently implement regulatory provisions pursuant to the NSP 2011 Act, public radio and TV broadcasters were under direct obligation to promote the idea of the census (information campaign). The objective of this requirement was to ensure that the public has the best possible understanding of the census idea. The normative assumption was to provide information on the idea of the general census to the highest possible number of persons, in a readily accessible form, ensuring, at the same time, that the message would be understood. The legal framework created by the Act resulted in a higher participation in, and better public perception of, the census. This certainly had an impact on the completeness and quality of results obtained.
Particular provisions of the NSP 2011 Act introduced appropriate criminal penalties with the objective of securing precise, exhaustive and reliable information in response to questions asked in the census. The following cases were subjected to criminal penalties involving fines:

- failure to provide available data covered by the census, despite the obligation to do so pursuant to the Act;

- refusal to provide precise, exhaustive and reliable answers to questions designed to solicit data specified in the Act and in the Annex to Regulation No 763/2008.

[1] The consolidated text of the Act was published in the Journal of Laws of 2012, item 591, as amended).

[2] This Act was published in the Journal of Laws No 112, item 1198, as amended).

The General Census Commissioner, i.e. the  President of the Central Statistical Office, was in charge of the census work. The following persons worked as the deputies of the General Census Commissioner:

- the Director of the Central Census Office;

- persons appointed by the President of the Central Statistical Office.

The Central Census Office (CBS) was established by an Instruction of the President of the Central Statistical Office which set out the organisation and composition, as well as specific tasks of the CBS.
The following teams were included in the  Central Census Office's structure:

- a Team for organisation and logistical services for censuses;

- a Team for the integration of administrative sources;

- a Team for the preparation of legal regulations and legal services for censuses;

- a Team for financing and financial services for services, and conducting tender procedures;

- a Team IT services for censuses;

- a Team for promotional, popularisation and typographical services for censuses;

- a Team for personnel services for censuses;

- a Team for the quality of censuses;

- a Team for the modernisation of the National Register of the Official Territorial Division of the country (TERYT).

A working group for NSP 2011, operating within the Methodology and Analyses Team, provided specialist support to the Central Census Office.
Within the Methodology and Analyses Team working subgroups for the use in censuses of the public administration information systems were created. They were headed by directors of selected regional statistical offices.

The Secretariat, established within the Central Census Office, was in charge of the census documentation in accordance with the principles of the PRINCE 2 method.
The census organisational structure was hierarchical, corresponding to the territorial division of the country, and to the structure of data collected in the NSP 2011.
The levels were as follows:

- Central level;

- Voivodship level - Voivodship Census Offices(WBS);

-  Gmina level -  Gmina Census Offices(GBS).

Voivodship and  Gmina Offices were established in appropriate time, indicated in the timetable for the census.
Deputy Voivodship  Census Commissioners were in charge of the work of Voivodship  Census Offices and  Gmina Census Commissioners were in charge of the work of  Gmina Census Offices.
For the duration of operational activities connected with the collection of data:

(a) in the Central Census Office the following units were established:

- the Census Management Centre (CZS), responsible for the operational management of the census, and

- the Centre for Processing Census Data(CPDS), responsible for the administration of the census information system  were established in the Central Census Office.

(b) ) in  Voivodship Census Offices the following units were established:

-  Voivodship Census Management Centres(WCZS), responsible for the operational management of the census at the regional level, and

- Voivodship Call Centres(WCC), responsible for the carrying out of the census at the voivodship level, using the CATI method.

Staff were appointed in Voivodship Census Offices responsible for organisational and financial issues and for census systems administration (members of Voivodship Census Offices, including voivodship administrators), as well as operational staff responsible for the carrying out of the census on the territory of a given Voivodeship(WCZS and WCC).
In addition, statistical interviewers were appointed in every Voivodship Census Office for the duration of data collection. The number of statistical interviewers was decided by the Call Centre Manager on the basis of the number of available telephone numbers to dwellings designated for a full CATI interview.
Approximately 18 thousand  gmina leaders and census enumerators were appointed in  Gmina Census Offices.
Census enumerators were appointed by Directors of Census Offices at the request of the  Gmina Census Commissioners. The CBS in consultation with WBSs agreed a maximum number of candidates for  census  enumerators positions for each  gmina.  Gmina leaders recruited candidates accordingly. These candidates received training as indicated in the training schedule. The number of census enumerators (i.e. persons actually appointed to carry out census work) was also agreed through consultations between CBS and WBS.
A total of approximately 26 000 persons participated in the running of the NSP 2011 (this number includes all the staff of Voivodship and  Gmina Census Offices, as well as all the census enumerators).
The diagram below illustrates in figures the organisation of the census at the CBS, WBS and GBS levels.

Not available.

In Poland, the protection of confidentiality of information regarding individuals is one of the key principles governing the manner of dealing with data collected during statistical surveys, including during the census.
The obligation to comply with  statistical confidentiality in public statistics is laid down in Article 10 of the Act of 29 June 1995 on public statistics (Journal of Laws No 88, item 439, as amended, link: http://www.stat.gov.pl/bip/56_PLK_HTML.htm), which reads as follows:
"Individual and personal data  in public statistics, collected during statistical surveys, are confidential and enjoy special protection; these data may only be used for the purposes of studies, preparation of data sheets, and for statistical analysis. They can also be used by public statistics services for the preparation of the sampling frame for statistical surveys conducted by these services. Making individual and personal data  available, or using them for purposes other than indicated above is prohibited (statistical confidentiality)."
The question of protection against the disclosure of individual data collected during the NSP 2011 is regulated by Articles 10 and 11 of the Act of 4 March 2010 on the National Census of Population and Housingin 2011 (Journal of Laws No 47, item 277, as amended, link to the Act:

http://www.stat.gov.pl/cps/rde/xbcr/gus/ustawa_nsp2011_04032010.pdf)

In view of the fact that, in accordance with Regulation No 1201/2009, the source of information was a  sample survey which by its very nature is an estimate (because of the  generalisation of data collected from the respondents), it was not necessary to apply the the methodology used for safeguarding confidentiality, called the Statistical Disclosure Control (SDC).
A detailed analysis of the scope of published census data demonstrated that within the context of statistical confidentiality there is no risk whatsoever of disclosing personal data or sensitive characteristics.

Data are made available 27 months after the end of the reference period (March 2014)

n accordance with the information release policy adopted by the Central Statistical Office (CSO), data from the 2011 Population and Housing Census (NSP 2011) are made available in accordance with the provisions of the Act on the National Census of Population and Housing in 2011 and of the Act on Public Statistics, and in particular in accordance with the so-called "3R principle" (Article 14.2 of the Act), stating that: "The processed statistical information compiled in public statistics is accessible to everybody on an equal footing,  according to impartiality principle, and is disseminated simultaneously. This applies in particular to access to basic figures and indicators". The Central Statistical Office (CSO) disseminates statistical data through all access channels (website, e-mailing, telephone information, as well as direct contact through statistical information centres). Each time information on NSP 2011 is published, it can also be found in the internet "Newsletter” and in the RRS system.

Data collected during the NSP 2011 are made available in the form of:

1. "News releases" disseminated ad-hoc during monthly open press conferences of the President of the Central Statistical Office , and, simultaneously (when the conference begins) on the CSO website. Releases are also sent at the same time via electronic mail to registered data recipients (246 recipients, mainly representing media, analytical companies and financial institutions). Information about dates and hours of publication of notes are sent together with the invitations to press conferences.

2. Publications regarding the census are made available simultaneously in paper form and in electronic form on the CSOwebsite. The timetable for publication of information is available in the annual publishing plan of the Central Statistical Office (CSO). In addition, information is provided at monthly press conferences as regards publication announcements for a given month. 

3. Data in CSO databases (e.g. the Local Data Bank, Geostatistics Portal).

4. Implementation of orders and requests from users, addressed to the CSO Information Department.

5. A special bookmark NSP 2011 on the CSO website.

6. Media interviews given by the CSO Press Spokesman and CSO experts (249 interviews were given to media in the years 2011-2013 regarding NSP 2011).

Data on population and housing censuses are disseminated every decade

 Press releases regarding the Population and Housing Census in 2011 (NSP 2011) are made available ad-hoc, published on the CSO website, and sent by mail to subscribed groups of recipients. They take the form of a PDF document and/or Excel tables. Link to the NSP2011 data repository http://www.stat.gov.pl/gus/12773_PLK_HTML.htm

Responding to wishes expressed by the recipients of information on the population and housing census, tabular and analytical publications take the form of printed books (but they are also available in electronic format).
All annexes to publications are prepared on CDs (editable Excel), attached to book publications. They are also available on CSO websites and on the websites of regional statistical offices. This applies to all survey areas covered by the Population and Housing Census in 2011 (NSP 2011).
Tabular and analytical data for publication can be divided into the following categories:

1) national (with data concerning the country as a whole, data concerning regions, separately for urban and for rural areas, and data concerning Voivodeships);

2) regional (with data concerning  a Voivodeship concerned, its subregions, districts subdivided into urban and rural areas, as well as important information regarding communes in each Voivodeship).

The Analytical Microdata Base (ABM) is designed as the main element for processing result information and for making data available.
In the Population and Housing Census in 2011 (NSP 2011) SAS INSTITUTE's tools were used in view of their comprehensive functionality in respect of collection, integration, cleaning and processing of data and preparation of advanced analysis of reports and their presentation. The efficiency of the approach selected was also important.  It made it possible to efficiently process data obtained during the census, it provided rapid access to the results, and helped to ensure safety of, and control of access to, collected data.
The process of making data available under the ABM system includes:

- the preparation of products to be made available;

- the management of products made available;

- the monitoring and analysis of questions asked by users.
The module External Users Application (AUZ) plays an important function within the Analytical Database (ABM) in making data available. It supports monitoring and analysis of information needs of users as regards census data.
The AUZ application is a dedicated tool created to cooperate with the ABM system. This tool is intended for external users who, through this tool, can perform actions related to the servicing of the ABM system's metadata, to the management of products and meeting the requirements, and to the management of the quality of products produced. The main functionalities of the AUZ application are presented below:

- recording (reporting) the needs of internal users;

- review of products;

- product management;

- review of definitions of quality measurements and their reference values;

- review of actual (measured) values of quality measurements for data, processes, and products;

- gathering quality reports;

- review of metadata received from the Central Metadata System.

The level of access to different functionalities of AUZ is steered by rights of access granted to different users.
Depending on the method of publication of census results, these results are presented as:

- data aggregated in pre-defined tables, to which everybody has access;

- data created by users on the basis of microaggregates;

- data prepared by statisticians, on request;

- results of analytical work, conducted on data in OLAP cubes, or in a  set of individual data which are not identifiable;

- graphic presentation of data (charts, cartograms);

- visualisation of results of the census, using CSO's own tools.

Different forms of dissemination of census data, and in particular an extensive set of tables published and of pre-defined tables, available in the ABM system and in other databases, meet essential requirements of a wide range of users at the national and regional levels. Pre-defined objects, i.e. aggregates or multidimensional cubes constitute the basic source of data for external recipients, but also for the internal ones. It was assumed that it would be possible to calculate approximately 90% of statistical tables on the basis of previously prepared aggregates in OLAP cubes.
The users of the results also have a possibility to calculate themselves simple correlation tables, through the access to ABM and to the Metainformation Subsystem (PM). At the same time, tables which require data processing (calculation) according to individual, special requests made by recipients, covering non-typical territorial sections, wider data correlation, or non-standard grouping of data, will be prepared by specialist statistical units, equipped with an appropriate IT structure and availing of trained human resources.

Internal users (these are mainly statisticians) have guaranteed full access to individual (non-identifiable) data from the 2011 census, while for the external users a special application standardises the access. External users, and in particular science and research circles, have a possibility to carry out research work based on individual (non-identifiable) data from the 2011 census.
In Analytical Microdata Base (ABM)  SAS tools are being used.. However, it is possible to send data in other formats, such as e.g. csv., xls.

Geostatistics Portal
As a result of the use of GIS technology, statistical information collected during the Population and Housing Census in 2011 (NSP 2011) enhanced with geospatial data, are presented in the Geostatistics Portal.
The Geostatistics Portal is a modern approach which makes it possible to provide a cartographic presentation of data collected during censuses. It has information collection and presentation functions, as well as a function for making information accessible to a wide circle of recipients, including public administration, entrepreneurs, individual users, and scientific research institutions. A comprehensive solution is adapted to European standards, and all data, through processing, are presented in a de-personalised format, safeguarding statistical confidentiality.
The results of censuses were processed in the Analytical Microdata Base (ABM), which, using appropriate IT tools, generates different types of aggregated data and statistics in the form of tables and multidimensional cubes. Aggregates for the Geostatistics Portal were also prepared in the ABM, and they were replicated (copied) to the Portal's database.
A simple interface of the Geostatistics Portal makes it possible for the users to have quick and easy access to the processed statistical information. The users of the portal have the possibility to select a domain from a drop-down list box, or to find a subject through a search engine. Data are presented using such methods of cartographic presentation as choropleth maps and diagram maps. A portal user has a possibility to set his own parameters for thematic phenomenon visualisation, including the aggregation level (region, Voivodeship, sub-region, district, commune), number of classes, class calculation method, colour scale, transparency range, visibility of borders of territorial division units, labels, measure unit, symbols, and colours of the diagram.
In addition user has access to basic tools used i.a. to identify objects,  to look for localities, to measure the surface of an area (polygon)  indicated on a map. The Portal makes it possible to print a selected area of a map and export it to a selected format. It also gives a possibility to generate a report and to save it as a text file (.doc) or a table (.xls).
In view of the fact that the President of the Central Statistical Office in Poland (who is the leading authority responsible for two themes of spatial data) is required to meet the obligations contained in the INSPIRE directive, a WMS (Web Map Service) search service was developed and made available via Portal. WMS is a method of making data available through a map server. The server also determines its capabilities in that respect. The map images are prepared on the basis of geographic parameters contained in the database and returned to the client in such raster formats as GIF, JPEG, or PNG. Consequently, the Geostatistics Portal is open to other external services from which spatial data can be downloaded through this service.

Local Data Bank
Census data are also made available through the Local Data Bank (BDL). Organised and made available via the Internet, this provides the largest in Poland range of information regarding the socio-economic situation, the demographic situation and social issues, as well as the state of the environment, describing the situation in Voivodeships, districts, and  gminas as units of the State's social and administrative organisation. It also describes the situation in regions and sub-regions which constitute elements of the nomenclature of territorial units for statistical purposes. This database also provides access to data from individual domains studied at the lowest available level of territorial division during the census.

Selected methodological aspects regarding the Population and Housing Census in 2011 taking into account the objectives of the census, legal bases, method of conducting the census, scope of data and data sources, the scope of subject areas covered and dissemination of data are available at the following address: http://www.stat.gov.pl/gus/5840_15211_ENG_HTML.htm

Detailed documentation describing procedures for the management of the census process, regarding data quality at different stages of their processing, was collected in the metainformation system, linked to the Operational and Analytical Microdata Base.

In view of the methodology adopted to carry out the census (the mix mode method), two kinds of procedures were used to assess the quality of data.  On the one hand, an assessment was carried out of data collected through questionnaires (both in a full survey and in the sample survey - short form in which data entered originated from administrative sources, CAxIchannels - deduplication), and, on the other hand, the sample survey itself was also assessed.
Assessment procedures for data originating from questionnaires (including calculated measurements and indicators) are described in detail in point 12.2. This point also describes the preparation of the sample survey (sample selection, sampling scheme, generalizing from sample data, random errors). Another important stage in the assessment is the  post-enumeration census, which was also described.

In order to monitor the quality of data obtained through different channels, appropriate procedures were prepared at each stage of work.

I. Ensuring the quality of data obtained on the basis of forms

1. Electronic forms for the full – scope survey (short questionnaire), for  sample  survey (long  questionnaire), and complementary surveys (homeless  persons and persons in collective living quarters) included range check, logic control, steering, and descriptions for help function (term definition, guidelines for respondents).

2. In addition, a quality assessment of individual features was made for the purpose of the full survey whose short questionnaire, for the record, was initially supplied with the basic  data from registers and from information systems, and respondents could verify data through the  Internet-based self-enumeration (CAII). The following procedures were developed for making this assessment:

a) The completeness of variables used to generate hints in the short questionnaire was determined (by mapping variables from registers and information systems on variables/questions from the questionnaire used in the full survey).

b) The rate of completion of variables was assessed. Variables were specified in accordance with logical dependencesin the questionnaire.

c) The covering of variables was analysed. It was assumed that if data for the questionnaire were 80% covered, the questionnaire was considered complete. However, as a matter of principle, each person had a possibility to verify/ complete data through computer-assisted web interviewing (CAWI). If for a particular record there was no value derived from a specific variable (specific variables), the questionnaire for such a record/ person was sent for completion through a CATI or CAPI channel, depending on the amount of missing information. The following coverage indicators determined the channel to which a questionnaire would be sent:

- indicators for monitoring the completeness of the survey;

- indicators for completeness of the address point.

3. Deduplication of questionnaires received through different channels was carried out in order to obtain one unique questionnaire which would ensure that the full set of information was received. Specially prepared algorithms for calculating measurements were used in the deduplication procedure. These algorithms were assigned to both personal and housing questionnaires.   In the process of selection of the best questionnaires for CAxI layers it was assumed that in the starting set, i.e. in the set of all questionnaires in the CAxI sub-system, there might have been many housing questionnaires for one housing unit and many personal questionnaires for the same person. This would result, i.a. from several attempts to log-in, from technical difficulties, or from telecommunications difficulties. As a result of the process composed of

- a selection procedure for the housing questionnaire;

- a selection procedure for the personal questionnaire from the sample  survey;

- a selection procedure for the personal questionnaire from the full survey;

- a selection procedure for the personal questionnaire in cases where there was a relevant questionnaire from both the full and representative surveys;

one, most complete questionnaire for the person and the housing unit was identified in CAxI layers.

Sets of personal questionnaires for a housing unit opened a sub-set of selected questionnaires used for further processing of results.

II. Determination of the final scope of the sampling frame for addresses/housing units

Verification of persons in the register of addresses/housing units.
The address and housing register covering houses, housing units, collective living quarters, and persons who have a PESEL number (PIN-Personal Identification Number) were the basis for carrying out the census. However, it should be noted that the list does not include persons without the PESEL number (e.g. newborn babies, foreigners who registered after 4 January 2011, and  homeless persons without the PESEL number). In this connection, it was necessary to develop procedures which would add to the list persons who participated in the census through different census channels (CAWI, CAPI, CATI and off-line), and to eliminate persons indicated in the census as deceased.
The following stages of proceeding were taken:

(a) Addition to the table "Persons" in the list of addresses/housing units, of records of persons who participated in the census off-line, identified by the  PESEL number, and, possibly, also by providing personal data.

(b) Addition to the table "Persons" in the list of addresses/housing units, of records of homelesspersons.

(c) Addition to the table "Persons" in the list of addresses/housing units, of records of persons entered on the forms used to survey persons in collective  living quarters. The PESEL number was used for identification of these persons.

(d) At the end of the census the list of addresses/housing units was supplemented in the table "Persons" by adding records of persons which were entered in the forms for full and sample  surveys.

This applied in the following cases:

a) newborn babies without a PESEL number;

b) foreigners without a PESEL number;

c) persons who failed to find their names in the list of addresses/housing units, even though they had a correct PESEL number;

d) persons with PESEL numbers assigned after 4 January 2011.

III. Assumptions taken for the sample survey.

In order to ensure the quality of the sample survey, separate procedures were taken into consideration, which took account of the following stages of work:

1. Creation of the the sampling frame for housing units

Stages of creation of the the sampling frame for housing units included:

1) creation of an integrated register of addresses/housing units on the basis of records of addresses/housing units

At the initial stage, an integrated register of addresses/housing units was created. The list was a specification of variables necessary for managing the census, for the authentication of variables transmitted between CAxI channels, and for a random selection of housing units to be included in the sample census. The basis for creation of the register was sets of data originating from addresses/housing units records prepared on datasets from the end of October 2010. These datasets were created on the basis of data from the TERYT register for each commune (gmina – the smallest territorial unit), linked with information from communes' registration records , with the addition of data from the national population register PESEL. Data in the list were updated by communes' census offices in accordance with the situation on 4 January 2011.

2) verification of the list in the pre-census  survey

During the pre-census  survey, census enumerators carried out verification of all address points within the area of districts assigned to them, comparing them with items included in the register of addresses/housing units subjected to the pre-census  survey. The objective of the pre-census  survey was to approve or to modify address points specified in the list and to delete non-existing address points, or, possibly, to add new address points, where there were residential buildings, and non-residential buildings with housing units (e.g. collective living quarters such as e.g. student houses) which were not included in the register.

3)completion of the list with additional variables and creation of a sampling frame for the sample  survey

Furthermore, information originating from other registers and information systems of statistical databases was added to the list of addresses/housing units in the Operational Microdata Base (OBM). Additional information was included in the list with a view to improving the quality of data gathered in that register and to providing information needed for the stratification of random selection. During the verification of data on the register, criteria were established (variables and values thereof), which were used to create more homogeneous groups (stratification) of units to be included in the random sampling.

The following items were excluded while establishing the sampling frame:

a) collective living quarters not including any dwellings,

b) locked facilities and dwellings located therein,

c) Dwellings in collective living quarters constituting locked facilities

d) semi-permanent housing unit

e) uninhabited housing units, destroyed as a result of natural disasters, in particular floods. .

As a result, the sampling frame covered dwellings occupied by persons registered or non-registered for permanent or temporary stay, together with unoccupied dwellings which were being repaired, in which tenants were changing, or newly-constructed dwellings. Buildings recorded under the same address were considered in the sampling process unless their number exceeded two. The dwelling sampling frame was updated in the course of the pre-census survey, as a result of which some buildings which were not previously included in the register were also added by the sampling survey.

These buildings were not included earlier in the lists.

2) Variables taken into account in the sampling frame

For the purpose of the sample survey, the reference list was supplemented with a set of information concerning each dwelling, which was then transferred to the sampling frame, constituting the basis for the ultimate selection of the stratification criteria:

a) a territorial identifier;

b) location of the building/dwelling on a territory affected by floods or by another natural disaster;

c) number of  dwelling in a multi – dwelling building;

d) location of a dwelling in a multi-dwelling building ;

e) year of completion of building construction

f) number of persons in a dwelling;

g) number of persons registered for permanent residence;

h) presence of a foreigner in a dwelling;

i) presence of a working person (with social insurance), of a retiree or a pensioner, or of an unemployed person in a dwelling; 

j) presence of a disabled person;

k) presence of a  user of an agricultural holding and of a utilised agricultural area;

l) location of a dwelling in a gmina with a proportion of a (national or ethnic) minority of at least 10%.

The values of variables, as stratification criteria, were diversified  for urban and rural areas. he choice of criteria was finally determined in the course of trial sampling and included the following variables: territorial identifier; location of a dwelling in a multi- dwelling building; number of persons in a dwelling; presence in the housing unit of a working person (with social insurance), of a pensioner, or of an unemployed person; presence of a working person (with social insurance), of a retiree or a pensioner, or of an unemployed person in a dwelling 3) Allocation of a sample in different districts

The basic objective of the sample survey carried out under the NSP 2011 was to obtain information about the social and demographic situation at NTS4 level (poviats). Thus, it was necessary to divide the 20% sample of dwelling  (the percentage set for the survey for Poland) between districts NTS4 (LAU1). This was achieved using the root square allocation method. This method is a compromise between proportionate allocation and allocation ensuring the same precision for all sub-populations. Assuming that proportional random sampling was used, the sample would constitute 20% of a poviat population. . As the precision of results, i.e. the size of the sampling error, depends on the number of units in the sample, proportional sampling would result in an insufficient precision for a number of smaller poviats. . On the other hand, in using the alternative method, we obtain roughly the same precision of results for all districts, but at the expense of a significant "flattening" of the sample size. As a result, the sample size, and consequently the work input in the carrying out of a census would not be very different between large and small poviats. For this reason, the square root allocation method was adopted as a sample division method:. the number of dwellings subject to sampling in particular powiat is proportional to a square root of population number of dwellings and is given by the following formula:

In which:

n* - assumed sample size for Poland;

Np - number of  dwellings in a p-district.

The sample size for individual poviats was calculated using the above-mentioned formula. If the capital city of Warsaw was treated in the same way as any other district (poviat), it could make it impossible to obtain reasonably precise results for individual urban districts (dzielnice) of the city of Warsaw. The average value from the above-mentioned values, i.e. 87.5 thous. dwellings, was applied as the final sample for the city of Warsaw. This value was deducted from the assumed sample size for Poland, i.e. from 2 631  thous., and only then was the root square allocation for 378 poviats carried out. Samples in the smallest poviats (Beskidzki and Sejneński) were 3200 dwellings (49% of the population number of dwellings), while the largest sample (outside Warsaw) was recorded for the i city of  Łódź with 23 thous. dwellings, i.e. 6.9% of the number of dwellings in this city with powiat status.
In Warsaw, Łódź, Cracow, Wrocław and Poznań (the largest Polish cities), the sample distribution between different urban districts (dzielnice) was also carried out using the root square method. In cities other that Warsaw, in view of a small (4 or 5) number of urban districts (dzielnice), it was not necessary to increase the size of the sample, as was the case in Warsaw. Sample sizes laid down for different urban districts in these cities ensured that the results for these urban districts (dzielnice) would not be less precise than in the smallest districts (powiats). However, one should remember that obtaining results for urban districts (dzielnice) in the five largest cities is a matter of secondary importance in relation to the essential objective of the census, i.e. obtaining precise results for districts (powiats).

4) sampling scheme

A one-level stratified sampling scheme was used with a view to selecting the sample with a given number of units. Before the sampling process began, the sampling units (dwellings) were grouped into strata in order to increase the sampling efficiency. A differentiated approach to stratification was applied, depending on the poviat and gmina type.
In urban areas – powiats, and in districts and representations of the largest five cities, and also in other specified larger cities without powiat status, the first stage entailed dividing all dwellings into two categories:

a) Dwellings in blocks of flats,

b) Other dwellings.  

An indicator of the number of dwellings in the building in which a given dwelling was located served as the criterion for dividing dwellings into the reference categories. The category of dwellings in blocks of flats comprised all dwellings for which the value of the reference indicator exceeded the median. Then, in each of these two categories dwellings were stratified according to the number of persons in a dwelling, which was followed by a further division into four groups in terms of: The presence of a working person in a dwelling,

b) The presence of a retiree or pensioner in a dwelling, in case of absence of a working person,

c) The presence of an unemployed person in a dwelling, in case of absence of persons mentioned in (b),

d) Dwellings with other persons.

Dwellings located outside blocks of flats additionally comprised the category of a dwelling with  an agriculture holding user
Stratification based on the number of persons living in a given dwelling was an important factor which had an influence on the precision of results, as it reversed the negative effects of diversified the number of dwelling occupants. The efficiency of this stratification stagedepended on the correlation of the number of persons in the dwelling recorded in the sampling frame with the actual status. Stratification based on other variables had a positive impact on census results linked with the economic activity.
In other poviats, the first stage comprised stratification by gminas, where urban and rural gminas were considered two separate gminas. In towns, the stage of dividing dwellings into dwellings in blocks of flats and other dwellings was excluded, and the stratification proceeded in the same way as in the case of dwellings located in big cities outside blocks of flats in cities.In rural  gminas, at the first stage  dwellings were divided into two categories:

a) dwellings  with a  user of an agricultural holding;

b) other  dwellings.

In the first category, stratification was carried out in respect of the number of dwelling occupants, and subsequently, as far as possible, there was a further stratification based on the area of their agricultural holding (two, and possibly three area size-based groups, depending on the number dwellings with a user of an agricultural holding in a gmina In the second category dwellings were stratified in the same way as in small towns.
In some powiats the stratification concept presented above could lead to establishing very scattered strata  In some powiats the stratification concept presented above could lead to establishing very scattered strata. As a result, in the course of establishing the strata, the sampling programme simultaneously checked whether the strata established complied with the requirement of the minimum number of dwellings. Strata comprising  insufficient number of dwellings were combined with the adjacent strata.  The assumed hierarchy of criteria of so-called strata splicing was reverse to the hierarchy assumed for strata creation

Once all strata were established, the number of samples to be selected in each stratum was determined. It was assumed that the sample will be allocated proportionally to all strata. This implied, among others, that the sampling fraction determined through square root allocation for a given poviat was applicable to all gminas in this poviat, and to all strata established within a gmina.

5) Effectiveness of the solution used

In order to see whether the scheme of selection on the basis of random sampling was effective, the following parameters were assessed at the poviat level:

- number of persons;

- number of  dwellings with a working person;

- number of dwellings with a pensioner, but without a working person;

- number of dwellings with a user of an agricultural holding;

- size of the utilised agricultural area.

At the same time, based on the sampling frame, values of the corresponding sums for the above-mentioned variables were calculated. Relative differences for the estimated parameters were calculated according to the following formula:

where:

ŷp - estimation of the sum of values of variable Y in district p, based on the random sample;

Yp - sum of values of variable Y in district p, based on the data from the sampling frame.

6) Generalizing of results from the sample survey

At the stage of processing of results of the sample survey, two generalisation (weighting) stages of results of that survey were used:

• stage I – weighting with the use of adjusted weights "from the fraction" which are opposite of the sampling fraction for dwellings  of that survey

• stage II – weighting with the use of calibrated weight for the survey units which are persons.Primary weights were established as the opposite of the sampling fraction for close to 70. 5 thous. strata l. It should be recalled that the objective of stratification was to separate possibly homogeneous sampling units. Weights applied within each stratum were identical. The initial fraction weights had to be adjusted, given that 13.7% of housing questionnaires were missing from the sample survey.

Adjusted weights, set out at the first stage, were used for generalizing the census results concerning dwellings. However, separate weights was introduced for single-family family buildings which comprise one or two dwellings, as well as for households and families. Such weights were calculated on a secondary basis through calibrated weights for persons forming households.
As it was necessary to integrate the results of the sample survey with the full census (in respect of essential variables regarding sex, age, and place of residence - at the poviat level, distinguishing the urban and rural parts), it became necessary to  introduce calibrated weights for particularpersons.
The purpose of calibration method applied for the 2011 census was to adjust the structures of sex and age acquired in the sampling survey to the structures of population according to sex and age, as established in the full survey. Its results constituted a reference population.
Calibration of weights was performed using the CALMAR  programme (Calibration on Margins).7) The algorithm used to establish the weights  dwellings in the sample survey

In order to obtain correct generalisations, it was necessary to adjust initial weights, based on the random sampling scheme used. The adjustment took into account both , non-response and information concerning the reasons for failing to obtain data from some of surveyed units. Since the sampling unit was  dwelling, the adjustment procedure used information assigned to the variable "reasons for failing to complete the form", where different reasons for  dwellings randomly drawn for sampling were coded.
Within each stratum coded at the dwelling sampling stage, the weight adjustment was determined, based on the sampling fraction defined for a given staratum. The adjustment consisted of using an adjusting indicator, calculated as the quotient of the number of housing units which should be surveyed, and the number of dwellings for which the survey was successful (the reverse of this quotient can be interpreted as the indicator of completeness). For the random sample of 2 684. 2 thous. dwellings, completed forms were successfully collected from 2 317. 7 thous. dwellings.

Cases categorised as being outside the population surveyed (i.e. where the absence of a dwelling was discovered, or where a dwelling was unoccupied, or in respect of which inheritance proceedings were being carried out, or where a dwelling was about to be renovated, or not yet inhabited), amounted to 140. 4 thous., i.e. constituted approximately 5.2% the samplewere considered sampling frame errors.
The adjusted weight assigned to a the dwellings surveyed in a given stratum was a quotient of the weight adjusted to the sampling (fraction) weight. In the case of strata for which the adjustment calculated was too large and exceeded the pre-defined threshold (set out at level 3), the procedure of “combining” adjacent strata was used and the adjustment was calculated until the required restriction was complied with. Such a procedure was used to prevent an excessive  diversification of weights, which increases estimators variance and has a negative impact on the precision of estimation.
There was a separate treatment of a part of a dwelling sample, added after the sampling, in the course of the pre-census survey. An additional 105. 4 thous. dwellings were to be surveyed, out of which 45 300 dwellings surveyed while 43. 1 thous. dwellings proved to be outside the surveyed population. In this part of the sample it was assumed that the sampling weights are equal to 1. The above-described adjustment algorithm was applied at the level of random strata, defined as poviats.

Weights adjusted in that manner can be used to derive global values (e.g. the total number of dwellings, number of occupied dwellings, number of sub-standard dwellings), and can also be used to estimate dwelling characteristics (e.g. dwellings by size).

Non-sampling errors in the Population and Housing Census in 2011
The basic source of data for assessing the occurrence and scale of non-sampling errors are the results of the post-enumeration census. However, it should be noted that the method and the manner in which the census was carried out (described in point 3.2 Preparation and collection of data) and the electronic form of the questionnaire with secured logical links guaranteed good quality of data, i.e. avoidance of duplication in the enumeration of persons, avoidance of possible addition of fictitious persons,  as well as avoiding omissions of persons and errors in the content (resulting from the absence of responses or errors in responses).

Nevertheless, it was decided to carry out post-enumeration census in view of the fact that post-enumeration  census  always accompanied censuses in Poland which were conducted in a traditional manner.
The objective of the post-enumeration  census was to confirm the completeness of the sample survey, the correctness of data obtained in the  sample survey, and conformity of this data with the actual situation. In view of statutory provisions, the post-enumeration  survey was conducted by statistical interviewers over the phone (using the CATI method). As a result, the sampling frame for  dwellings included only  dwellings where it was possible to establish the telephone number of at least one occupier. Whether this was a landline or a mobile phone was not important.
The census verification form included 14 questions. Random sampling was carried out within the sampling frame for dwellings prepared separately for census verification purposes.
The post-enumeration  census was conducted in the form of a sample survey. Out of 2 744 thous. dwellings that have been previously been drawn to a sample survey,, 80 thousand  dwellings (ca. 3%) were randomly selected.
The post-enumeration survey covered  dwellings where respondents opted for the Internet-based self-enumeration,  dwellings which were enumerated directly by census enumerators, or over the phone by statistical interviewers. It also covered  dwellings which were not covered by the census (for different reasons).
The following  dwellings were in principle excluded from random sampling for the census verification:

a) dwellings belonging to persons who participated in census by Internet using the short form despite the fact that their dwellings were drawn for a sample surveyb) dwellings in collective living quarters which were earlier drawn for a sample survey;

c) dwellings with 15 or more  inhabitants.

Sampling errors
Data to be used to calculate information for the hypercubes were obtained on the basis of the sample survey, based on random sample of approximately 20% of dwellings on national scale. The results of each sample survey retain sampling errors which can be evaluated on the basis of the theory of probability and mathematical statistics. The level of sampling errors depends on several factors: the size of the sample, the sampling scheme used, the size of the fraction of the random sampling in relation to the size of population surveyed, and on the variability of the feature surveyed.
Global values for the set of characteristics constitute the essential parameters calculated on the basis of data collected in the sample survey and presented in hypercubes. The majority of surveyed variables characterise the population of persons, while a smaller part applies to dwellings and buildings. In accordance with the requirements of the quality report, indicators concerning sampling errors were determined for 18hypercubes(QHC04-QHC24) containing estimates of the resident population for relevant aggregation levels, i.e. taking into account Voivodeships, regions, sex, and age groups.
The method of estimation and assessment of estimation quality for characteristics regarding population are described below.
The global value estimator for particular individual characteristics corresponds to a weighed sum which is calculated as follows:

Where:

'h' indicates the strata resulting from the dwellings sampling scheme;

'i' means  the dwelling  code, i.e. the sampling unit;

'j' means the person included as a dwelling occupant

 – - means the weight assigned to a given person from a given dwelling; this is the value recorded in the variable weight_per_population_first_person, i.e. after calibration, and

-means the value of the individual characteristics analysed, e.g. 1- if a person is unemployed,
0 – otherwise

For specific result tables it is necessary to prepare a special set of new characteristics, based on existing                                                                                                                                                                                                                                                                                                                                output data. For example, in order to analyse the populations by age group, dummy variables should be defined for specific age intervals; , additional variables should be defined as appropriate (e.g. taking into account division by sex).

To assess the quality of the global value estimator, so-called estimation precision indicators are designated. They allow users of the output tables  to correctly assess data. It was decided that precision indicators presented would be defined as relative standard errors (otherwise coefficients of variations, designated as CV, or as COEFVARI in hypercubes), in accordance with a formula:

where Var means the assessment of  the  estimator variance, calculated in accordance with a formula: 

Value means the number of dwellings in a given layer or sample surveyed, while  is the number of dwellings from the upper population stratum; value  may can be retrieved by adding up the adjusted weights which result from sample selection for the purpose of the sample survey.

This formula for the variance estimator is implemented in the SURVEYMEANS procedure, under the SAS system, where it is described as an example of the use of the so-called Taylor linear approximation method.
To obtain precision indicators at aggregation levels which do not correspond to strata used in the random sampling, a general algorithm of so-called domain estimation can be used. It consists of the use of a classical method for specially defined ancillary variables which are equal to the variable analysed for the relevant sub-population (domain) and which are zero-valued outside the relevant sub-population. In the SURVEYMEANS procedure, estimation in domains is carried out through the DOMAIN command.
A CV indicator can be used to determine the confidence interval within which the real value of the estimated parameter can be found with a specified degree of probability (so-called confidence level, e.g. 95%). For example, for a confidence level of 95%, such confidence limits are as follows: ± CV.

As an example, we can look at a quality hypercube QHC05 which applies to the economic status. Taking the values of available measurements as: GEO=PL, SEX=T, AGE=TOTAL, CAS=UNE, we obtain the estimated number of unemployed in Poland at 2 132 .8 thous., with a precision indicator equal COEFVARI=0.00164 (i.e. 0.16%). When setting the confidence limits, it can be stated that, with a 0.95 probability, the real number of unemployed persons was within the spectrum (2132.8-1.96*2132.8*0.00164; 2132.8+1.96*2132.8*0.00164), i.e. between 2 125 .9 thous. and 2 139 .7 thous.
As another example, we can take a hypercube QHC07 illustrating the distribution patterns of population by the size of their places of residence. Taking the values of available measurements as: GEO=PL12, SEX=T, AGE=Y_LT15, LOC= GE1000000, we obtain the estimated number of persons aged less than 15, residing in localities with more than 1 000 000 inhabitants (i.e. in Warsaw) at a level of 221 .5 thous.,  with a precision indicator equal COEFVARI=0.0073 (i.e. 0.73%). When setting the confidence limits, like in the previous example, it can be stated that, with a 0.95 probability, the real number of persons aged less than 15, residing in Warsaw, was within the bracket 218 .3 thous. - 224 .7thous..
Analysing the results of calculations of the estimator variance for tables regarding population, one can draw a general conclusion that the quality of results is very high for such a model of aggregation where the generalisation values are relatively high. This is a consequence of the fact that these results were based on relatively large samples of dwellings. If we consider cases where the estimated size of population is of the order of a few thousand persons, then in most cases the precision indicator is below 10%.
In the quality hypercube QHC04 it is possible to see many cases where the value of the COEFVARI indicator is zero. This is due to the calibration of weights and the alignment of population distribution for certain aggregation patterns with data resulting from a so-called full census (in accordance with data from registers). Such a conformity of population distribution from the sample  survey was ensured for the grouping by Voivodeships (regions) x sex x five-year age groups (up to 'Y80-84' group, older groups were merged for the calibration).
All calculations relating to estimation precision were carried out in the ABM environment.

The degree of under-coverage/over-coverage of population
In order to establish the quality of estimates  of the size of population in the country, in regions and in Voivodeships, an assessment was made of the degree of  under-coverage/over-coverage of population  resulting from inaccuracies in taking into account actual data on internal and foreign migrations, both immigration and emigration.
It was accepted that the size of population in Voivodeships on whose territory there are large cities - which are academic centres and which provide a significant number of workplaces - is slightly under-covered, and the size of population in adjacent Voivodeships is slightly over-covered. This is due to the fact that registers which were the basis for setting out reference population do not contain information on all internal migrations, and verification of registers data (through  Internet-based self-enumeration) was not done by all persons covered by the census.
Moreover, the size of population (in the country, in regions, in Voivodeships) was determined taking into account the numbers of registered emigrations, with the addition of information obtained through the Internet-based self-enumeration. Since not all emigrations are registered, and, for obvious reasons, not all persons who resided temporarily abroad for at least a year took part in the Internet-based self-enumeration, it was considered that the number of emigrants residing temporarily abroad for at least a year, which should be excluded from the residing population was under-covered, and therefore was the cause of over-coverage of the size of participation.
At the same time, the number of immigrants residing temporarily in Poland for at least a year, recorded in the census - as in previous censuses - was clearly under-covered, which resulted in under-coverage of the total number of the resident population.
Taking into account the above-mentioned components which influence the population size, the resulting estimated value of under-coverage and over-coverage of population was determined by territorial sections (for the country, for NUTS1 and NUTS2).

Imputation and removal of records

Imputation

Unit  imputation
The bases for determination of persons entered on the forms were registers and information systems completed with information obtained through surveys using questionnaires. The process of creation of the set of data records reflecting the entire recorded population of persons (reference population) was based on the use of register data, their verification and updating on the basis of data obtained during questionnaire-type surveys. In effect, this process did not cover typical unit imputation procedures, i.e. adding full personal records from - or on the basis of - sources other than those accepted as the basic source of information about population, i.e. registers and questionnaire-type surveys during census.

Item imputation
During validation work on sets of census data, there was imputation of missing data (data missing as a result of lack of  responses) in respect of some of the variables, i.e. item imputation was used. In most cases the deductive imputation method was used, based on a deterministic approach, taking into account dependencies between variables.

Removal of data records
During verification, a relatively small number of data records were removed from the total of data originally introduced to personal data sets. These were mainly records introduced many times for the same persons, largely as a result of errors in entries regarding identifying variables (e.g. PESEL number), as well as records containing data on persons incorrectly included in the surveyed population (e.g. in view of the date of birth or the date of death).
As regards the subject of  dwellings and buildings, it was necessary to apply record imputation in the case of the sample survey. In the original version, approximately 32 thousand uninhabited  dwellings, in respect of which no census interviews were conducted, were excluded from the survey. However, having analysed the reasons for the lack of  responses, it was decided that  dwellings under renovation, reconstruction, etc., should be included in the housing stock, uninhabited. The number of records for these  dwellings constituted approximately 1.3% of the  dwellings population checked in the sample survey.

1. The sampling scheme of the post-enumeration survey The post-enumeration census for the Population and Housing Census in 2011 was planned as a sample survey. The sampling frame consisted of dwellings drawn up earlier for the sample survey (2 744 thous. dwellings). The post-enumeration census covered dwellings in which respondents opted for Internet-based self-enumeration, dwellings enumerated directly by census enumerators, or over the phone by statistical interviewers. It also covered dwellings where the census was not carried out, for different reasons, in the period from 1 April to 30 June last. There was an additional condition imposed that a housing unit should have a telephone. This resulted in the reduction of the sampling frame to 1 386 thous.dwellings. The random sample for the post-enumeration census was to include approximately 80 thousand dwellings, i.e. 2.5-3.0% of all dwellings checked in the sample survey.

The stratified sampling scheme was used, where strata were defined as described below.

One of stratification criteria was the manner in which data were sourced in the sample survey, i.e. the contact channel with a dwelling examined in the census.
In addition to basic channels for sourcing data in the census, an agreed channel was added, to include dwellings which for different reasons were nor surveyed.  Within the established contact channels, division into deeper strata was determined for each poviats. Within this division, urban and rural parts were taken into account.  For the capital city of Warsaw, a further division into districts was done. Moreover, in the case of enumeration by a census  enumerator (through CAPI), a more detailed division of strata into two roughly equal parts was considered, determined according to a median of the variable "number of persons in a dwelling". 4 202 layers were obtained using this method.
The allocation of approximately 80 thousand units was done initially between channels, applying the rule of allocation proportional to the root square of the number of dwellings. The final division of the sample between deeper strata in a given channel was done using the proportional method.
On the basis of the determined sample allocation between 4 202strata, the sampling was carried out, using a sampling algorithm, without independent replacement in each of the strata. Calculations were carried out using the SAS system.

2. Analysis of results of the post-enumeration census.

The post-enumeration census was performed for 67 877 dwellings, i.e. for approximately 85% of the sample of dwellings for that survey. The main reason for the failure to perform the survey was the lack of contact and refusals to participate. In order to correctly generalise data, an adjustment of weights from the sampling was made, separately for groups defined as cross-sections of districts and contact channels (which were used in the sample stratification).  Adjusted weights were used in further calculations.

The effect of the census verification was the assessment of data quality, using the following measurements:

- Conformity index (CI), taking into account, jointly, the correlation of results of both surveys and variations of results of each of the surveys.

- Relative error (RE) of average values from measurements of each of the variables.

The conformity index is a generalisation of the correlation coefficient, generally known in statistics. It measures not only the interdependence of two variables, but also detects differences in standard deviations which characterise variability in individual one-dimensional distributions. However, the conformity index does not measure the shift-level, i.e. the error burdening of results. For this reason, the analysis is accompanied with an additional calculation of simple statistics in the form of relative errors. Such assessments, together with charts of distribution of variation, make it possible to identify systematic error burdening, if any.
The analysis of relative errors showed that there were no systematic differences for the variables surveyed (distribution of variation was around zero values). This applied both to dwellings variables and to population.
The conformity index was determined at the country level, and broken down by Voivodeships, by the method of conducting the sample survey in a randomly drawn dwelling (whether conducted by a census enumerator, by Internet, by telephone, or by other means), by the type of channel through which the census was conducted (CAPI, CII, CATI), and by the type of person providing responses in the census verification. The results obtained indicate that there was an absence of any significant differentiation of the value of indexes in respect of breakdown applied.

Below we present some of the values of the conformity index estimators, calculated for the whole country:

 The results obtained indicate conformity of both surveys (i.e. sample survey and post-enumeration survey) in respect of the majority of variables analysed.

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Depends on the availability of data transmitted by the National Statistical Institutes.

There are no particular reasons for data unreliability for this topicData processed under topic Place of usual residence are in compliance with the definition in Regulation 1201/2009.
Population with residence in Poland was derived from information concerning the character of the residence and the actual or intended time of residence of individual persons. This means that all persons present at the moment of census, residing or intending to reside in Poland (in the gmina) for a period of at least 12 months, were considered to be residents of the country ( gmina). Permanent residents who were outside their place of residence ( gmina) at the time of the census were included as residents only if the intended time of their absence was less than 12 months. If the intended time of their absence was a year or more, they were considered as residents in the place ( gmina) of their temporary residence. If they resided abroad, they were not considered as residents of Poland.
The same applied to foreign nationals residing in Poland on a temporary basis. Only those whose intended time of residence was at least 12 months were considered as resident in Poland.
Students were considered to be residents in the place ( gmina) of their studies. In the case of students studying abroad, they were not included as residents of Poland. Foreigners studying in Poland were considered as residents of Poland.
Young people attending secondary schools were considered as residents of gmina of their permanent residence (family home), regardless of the school's location.
Homeless persons were categorised as residents of a gmina where they were enumerated.
Permanent residents of Poland residing in collective living quarters were enumerated as residents of the  gmina in which collective living quarters were located. Foreign nationals residing in collective living quarters were categorised as residents if their actual or intended time of residence was at least a year. If it was less than 12 months, they were not considered to be residents of Poland.
Soldiers and persons on military missions, as well as diplomats and their families remained residents of Poland.

There are no particular reasons for data unreliability for this topic

Data processed under the topic Sex are in compliance with the definition in Regulation 1201/2009.

There are no particular reasons for data unreliability for this topic

Data processed under the topic Age are in compliance with the definition in Regulation 1201/2009.

There are no particular reasons for data unreliability for this topic

Information on marital status was prepared on the basis of the  sample survey and was determined on the basis of responses given by respondents. In the Polish census, information was obtained both for the legal marital status and de facto marital status.
The legal position regarding marital status for persons aged 15 years and more was defined as marital status pursuant to the law in force in Poland (the Law on Civil Status Acts). Polish law allows marriages for women aged 16 and more and for men aged 18 and more.
In accordance with the law in force, the following categories of legal marital status were specified:

- unmarried;

- married (including married couples in separation declared by a court, in accordance with the applicable legislation);

- widowed

- divorced.

Polish legislation does not provide for registered partnerships. Partnerships were determined on the basis of de factomarital status.
Pursuant to the provisions of the Act of 4 March 2010 on the Population and Housing Census in 2011 (Journal of Laws of 26 March 2010, No 47, item 277), an informal relationship means two persons living in the same household, who did not conclude a marriage in the form provided for under the Polish law, but whose mutual relationships are of a conjugal nature.

DeFacto marital status was also determined for persons aged 15 and more.
Information was derived in the secondary operation on the basis of the following data: legal marital status, date of marriage or date on which partnership commenced, and a voluntary question regarding the nature of the partnership (formalised in a civil registry office or in a church (religious community)) in which a person surveyed was at the critical moment of the census.

The following  categories of de facto marital status were defined:

-unmarried, i.e. persons who were never legally married and at the moment of the census did not live in cohabitation with another person (a common-law husband or wife);

- married, i.e. persons who have entered into legal marriage and the marriage still actually exists.. These persons declared that they formed a community by marriage,  irrespective of whether the spouses were enumerated together (in the same dwelling) or separately (e.g. in the case of the absence of one of the spouses due to education, work or the lack of a joint dwelling).

* Persons who remained to be legally married but who did not form a community by marriage, under a decision made by one or both spouses, and whose marriage was not dissolved by court (by the adjudication of divorce or separation), were not categorised as married and their de facto marital status was determined in accordance with the respondent's declaration, as being separated, or living in consensual union with another person.

-partner - consensual union relationships were defined within the same household, regardless of the legal marital status of persons living in consensual unions;

- widowed- persons whose legal marriage ceased to exist as a result of the the spouse’s death and who, at the time of the census, did not live in cohabitation with another person,

- divorced - persons whose legal marriage was legally dissolved as a result of  a court judgment and who, at the moment of the census, did not live in  consensual union with another person;

- separated - this category refers to persons who, at the moment of the census:

a) were in legal separation and did not live in consensual union with another person,

b) were still legally married but neither formed a community by marriage nor lived in consensual union with another person. Polish legislation does not provide for same-sex marriages. As a result, no information was prepared in the Polish census on same-sex relationships, either for legal civil status or for de facto marital status.

There are no particular reasons for data unreliability for this topic

Information on FST was prepared on the basis of the sample survey. The family nucleus is defined as two or more persons who belong to the same household and who are related as husband and wife, as partners in a consensual union (unregistered), or as parent and child. Thus a family comprises a couple without children, or a couple with one or more children, or a lone parent with one or more children. This family concept limits relationships between children and adults to direct (first-degree) relationships, that is between parents and children.
In accordance with Commission Regulation (EU) No 1201/2009 of 30 November 2009, the following categories of persons were defined:

1. Partners

a) Partners in a married couple

b) partners in a consensual union (unregistered). Pursuant to the provisions of the Act of 4 March 2010 on the Population and Housing Census in 2011 (Journal of Laws of 26 March 2010, No 47, item 277), an informal relationship means two persons living in the same household, who did not conclude a marriage in the form provided for under the Polish law, but whose mutual relationship is of a conjugal nature.

Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided.

2. Lone parents

3. Sons/daughters The term "sons/daughters" corresponds to the definition of the term "children". A child (son/daughter) refers to a blood, step- or adopted son or daughter (regardless of age or marital status) who has usual residence in the household of at least one of the parents, and who has no partner or own children in the same household. Foster children are not included. A son or daughter who lives with a spouse, with a partner in an informal union, or with one or more own children, is not considered to be a child.

4. Not stated - in the Polish census there are no persons included in that category (there are only persons with an established position in the family, or persons who do not form a family).

5. Not applicable - refers to persons who do not form a family nucleus.

There are no particular reasons for data unreliability for this topicInformation on HST was prepared on the basis of the  sample survey. The Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided.
Persons of no stated category living in a household. In the Polish census there are no persons included in that category (there are only persons within the family nucleus, or outside the family nucleus).
Persons of no stated category not living in a household - in the Polish census there are no persons included in that category (there are only persons living in a private household and persons not living in a private household, i.e. those living in collective living quarters, and homeless people).
Homeless persons (roofless) were not taken into account to establish the structure of households and families and types thereof.

There are no particular reasons for data unreliability for this topic

Information on CAS was prepared on the basis of the representative survey. The current activity status definition was used in line with Commission Regulation (EC) No 1201/2009 of 30 November 2009. In accordance with that definition, the basis for the breakdown of population into employed persons, unemployed, and economically inactive, is work, i.e. the fact of performing, holding, or seeking a job over a specified period of time. In the case of NSP 2011 the reference period was the week from 25 to 31 March 2011. The sequence of selection of individual subpopulations guarantees that each person will be classified under only one of three categories differentiated from the point of view of their status in the labour market.
Employed: This category includes all persons aged 15 or over who during the reference week (25 - 31 March 2011):

- performed for at least one hour any work for pay or profit, in cash or in kind, i.e. worked as an employee, worked on their own (or leased) agricultural holding, or carried out a self-employment job outside agriculture, and persons who contributed (without remuneration) to the running of a family-owned agricultural holding or a family business outside agriculture;

- did not work (for reasons such as, e.g. illness, holiday or vacation, stoppage in the enterprise's activity, bad weather, strike), but formally had jobs as employees or self-employed.

Contributing family workers who did not perform work in the reference week were considered as as persons without work.

The unemployed comprised all persons aged 15-74 years who met all of the following three conditions:

- they were without work during the reference week;

- they were actively seeking work in the period from 1 to 31 March, i.e. they had taken at least one of the following specific steps in order to find a job (irrespective of the effects of that action were): answering job advertisements; seeking job through relatives and friends, or directly in enterprises; endeavouring to organize an own workplace; or registering in an employment office as jobseekers;

- they were ready (available) to take up work within two weeks following  the reference week, i.e. in the period from 1 to 14 April.

Persons who had found a job and were waiting to start work within 3 months, and were ready to take it up, were also included in the unemployed category.

Persons economically inactive are persons aged 15 years or over who were not classified as employed or unemployed, i.e. persons who in the reference week:

- did not work , did not have a job, did not seek a job;

- did not work were looking for a job, but were not ready (able) to take up work within two weeks following the reference week, i.e. in the period from 1 to 14 April;

-  did not work or seek a job, because they had already found a job and were waiting to start it in a period of more than 3 months, or a period of up to 3 months, but were not ready to take it up.

Economically active - all persons classified as employed or unemployed, in accordance with the above-mentioned definitions.

Within the scope of the topic “Current  activity status” (CAS) the breakdown levels and categories of any groups and subgroups regarding persons were applied, whereas:
- in group CAS.H2.4. "Homemakers and others", the optional breakdown into categories 2.4.1 and 2.4.2  was not used

- additionally, category CAS.H 1.2.2. "Unemployed, previously in employment" included unemployed persons  for whom no information was obtained as to whether they had worked in the past (because of the absence of a separate code). This category covered 37 656 unemployed persons (8 915 records) after weighting.

- category CAS.H 3.2. "Not stated" included persons residing in collective living quarters and homeless people.

There are no particular reasons for data unreliability for this topicInformation on OCC was prepared on the basis of the  sample survey. In accordance with Commission Regulations (EC) No 1201/2009 of 30 November 2009, topics "Occupation", "Industry" and "Status in employment" were based on the same, place of work, identified as the main job.
The breakdown categories within the topic "Occupation" (OCC) applied to persons who were employed during the reference week, or who were unemployed during the reference week, but had been in employment before (occupation during the last period of employment).
Categories OCC.1. to OCC.10. of the breakdown "Occupation" correspond to the 10 major groups of the ISCO-08 (COM) classification.

There are no particular reasons for data unreliability for this topic

Information on IND was prepared on the basis of the  sample survey. In accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009, breakdown categories within the topic "Industry (branch of economic activity of the workplace)" (IND) referred to persons who were employed during the reference week (relates to the main job), or were unemployed during the reference week, but had been in employment before (industry they worked in during their most recent employment).
The categories IND.H.1. to IND.H.10.4. of the breakdown "Industry (branch of economic activity)" correspond to the 21 sections of the NACE Rev. 2 classification.

There are no particular reasons for data unreliability for this topic

Information on SIE was prepared on the basis of the sample survey. In accordance with Commission Regulation (EU) No 1201/2009 of 30 November 2009, the following categories of working persons were defined:
Employees. They included:

- persons hired on the basis of employment contracts (labour contract, commission contract, contract for specified work, appointment, election or posting) by public entities, cooperatives, social and political organizations, trade unions, private enterprises, as well as natural persons and private farms,

- persons performing outwork;

- apprentices (and persons in  traineeships ) with whom work establishments or natural persons entered into a contract on professional training or training in a specific trade, or training to perform a specific job, if they receive remuneration;

- persons hired on a family farm or in family business who receive agreed earnings or income (not necessarily in a monetary form), irrespective of the relationship with the household of the farm holder or the owner of family business.

The "employee" category was broken down into full-time employees and part-time employees:

- full-time employees are those whose regular working hours are the same as the customary hours worked in the entity under consideration, at a given post, or in a given profession/occupation. Full-time employees also include persons who, in accordance with the regulations in force work shorter hours, persons employed on the basis of a service contract or specific task contract, persons elected to a given position, or outworkers if they worked for at least 36 hours in a given week;

- part-time employees are persons who, in accordance with a concluded agreement, work shorter hours than the customary hours worked in the entity under consideration, at a given post, or in a given profession/occupation.

Self-employed persons. They included:

- owners, co-owners and leaseholders of individual agricultural holdings, working on these holdings;

- members of agricultural production cooperatives;

- agents in all agency systems;

- self-employed persons outside the agricultural sector (registered or non-registered); persons on whom registration as self employed (one-person economic activity) was imposed.

The self-employed category is broken-down into:

-employers (i.e. those employing at least one employee);

- self-employed persons not employing any employees.

Contributing family workers - persons who without a contractual - earlier agreed - remuneration help in running a family business, including running a family agricultural farm.
The breakdowns for the topic "Status in employment" (SIE) are designed to break down the total, and any subtotals of employment status relating to persons, who during the reference week were employed or who were unemployed, but had been in employment before
while:
in group SIE. 4.  Others ("Contributing family workers" and "Members of producers’ cooperatives") optional breakdown into 4.1 and 4.2 categories was not applied.

There are no particular reasons for data unreliability for this topic

Information on LPW was prepared on the basis of the sample survey. The location of the place of work is the geographical area in which a currently employed person does his/her job.
The term "work" refers to work done as an "employed person" as defined under the topic "Current activity status". The breakdowns for LPW are designed to break down the total of places of work and any subtotals in accordance with Commission Regulations (EC) No 1201/2009 of 30 November 2009, whereas
- in addition, in the codes PL, PL1 - PL6, PL11- PL63, working persons were also included in respect of whom no information regarding their place of work was obtained, adopting the rule that "the Voivodeship of place of residence = the Voivodeship of place of work" (in view of the absence of a separate code for working persons whose places of work locations were not determined).

There are no particular reasons for data unreliability for this topic

Information on EDU was prepared on the basis of the sample survey. Educational attainment refers to the highest level successfully completed in school or in another manner or form, recognised in accordance with the requirements of the educational system. The basis for recognising the specific level of educational attainment was a certificate (diploma) in respect of the level of studies completed, regardless of the method of completion (day studies, evening studies, extramural studies, part-time studies). Information on educational attainment was prepared in respect of all persons aged 15 years and over.
The following classification of educational attainment was used in the census:

1. Higher education

a) with an academic degree, at least a PhD;

b) with a Master's degree, MD degree, or equivalent;

c) with a degree of B.Eng., BA, B.Econ.Sc.

2. Post-secondary non-tertiary education

a) college diploma;

b) with leaving certificate (post-leaving certificate studies);

c) without leaving certificate.

3. Secondary education

a) vocational with leaving certificate;

b) vocational without leaving certificate;

c ) general with leaving certificate;

d) general with leaving certificate.

4. Basic vocational education

5. Lower secondary education

6. Primary education completed

7. Primary education not completed and no formal education

The above-mentioned breakdown made it possible to prepare data in accordance with categories in Commission Regulation No 1201/2009 of 30 November 2009.

There are no particular reasons for data unreliability for this topic.

The size of the locality is determined by the number of its inhabitants.
Depending on the number of inhabitants of a particular locality, an appropriate size symbol is assigned (LOC).

There are no particular reasons for data unreliability for this topic.

Information on POB was prepared on the basis of the sample survey.
Both the definition and the list with the official names of countries are in accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009. This means that in the Polish census information on the country of birth was collected (on the basis of international boundaries existing on 1 January 2011.) according to the place in which the birth took place.
In addition, information based on the declarations of persons was also included in the list with the official names of countries 3.1 and 3.2.

There are no particular reasons for data unreliability for this topic

Information on COC was prepared on the basis of the  sample survey. Both the definition and the list with the official names of countries of citizenship are in accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009.
It should be noted that pursuant to national regulatory provisions currently in force, in Poland a foreigner is a person residing in Poland who does not have Polish citizenship. In accordance with this definition, a person who has both Polish and another country's citizenship is not a foreigner.
In the  sample survey it was possible to indicate three citizenships, both for Polish citizens and for foreign nationals.
As regards the ‘Recognised Non-Citizens’ category, there is no such category in Poland.

There are no particular reasons for data unreliability for this topic

Information on YAE was prepared on the basis of the  sample survey.
This variable applies to any person who ever resided abroad.
The year of arrival is the calendar year in which a person established usual residence in the country.
If a person resided abroad several times (was a resident of another country), the year of arrival is the year of the most recent arrival in the country.

There are no particular reasons for data unreliability for this topic.

Information on ROY was prepared on the basis of the  sample survey. Both the definition and the breakdown categories are in accordance with  Commission Regulation (EC) No 1201/2009 of 30 November 2009.
In the Polish census information on residence one year prior to the census was not obtained directly. The information was derived from the date of arrival at the place of current residence and the place of prior residence. If a person arrived at the place of current residence before 31 March 2010, it was assumed that the person resided in the place a year prior to the census. If a person arrived after 31 March 2010, it was assumed that the person resided in that locality/country of previous residence a year prior to the census.

There are no particular reasons for data unreliability for this topic

The topic "Housing arrangements" covers the whole population and refers to the type of housing in which a person resided at the time of the census. This covers all persons who are usual residents in different types of living quarters, or who do not have a usual residence and stay temporarily in some type of living quarters, or who are roofless, sleeping rough or in shelters, when the census is taken.
Types of living quarters

Conventional dwellings (HAR_DW)
A conventional dwelling means premises composed of one or more rooms, together with auxiliary rooms. It is constructed or converted for residential purposes, is structurally separated (with permanent walls) within a building. A conventional dwelling has an independent entrance from a staircase, from a common corridor, a common mudroom, or directly from the street, from a courtyard, or from a garden.
An auxiliary room means an entrance hall, a hall, a bathroom, a toilet, a dressing room, a pantry, a storage room, and other rooms within a housing unit, which are designed to serve residential and other everyday needs of residents.
In the case of a multi-room dwelling or an individual house (a family house) housing two or more individual households, with separate rooms occupied exclusively by one of the households, a rule was followed that if within such dwelling or house there was at least one room (such as kitchen, bathroom or toilet) used jointly by all the resident households, such dwelling (house) was considered to constitute one housing unit. If that was not the case, i.e. the above-mentioned rooms were not used jointly, then the sets of rooms occupied by individual households were considered to be separate  dwellings.
Regarding the occupancy status of conventional dwellings, the dwellings were broken down into:

Occupied conventional dwellings
Occupied conventional dwellings were conventional dwellings which were occupied by one or more persons at the time of the census, and at least one of these persons was recognised as being the usual resident there. Temporarily occupied conventional dwellings were dwellings where one or more persons were enumerated during the census, but none of those persons were recognised as being usual residents in that area.

Unoccupied conventional dwellings
Unoccupied conventional dwellings were dwellings where not a single person was enumerated during the census, either as a permanent resident, or as a temporary resident.
For that category of  dwellings the reason was established as to why the dwelling was unoccupied.  Below is the breakdown of dwellings with reference to the reasons for which dwellings were reported as unoccupied:

- dwellings not yet occupied in new buildings or in buildings which underwent extension;

- dwellings unoccupied because of the change of the tenant for the new occupation (dwellings for rent or for sale);

- dwellings unoccupied because of renovation work or waiting for renovation;

- dwellings scheduled for demolition, or abandoned for different reasons where it was not decided whether they would be demolished or used for non-residential purposes;

- dwellings designed for seasonal or secondary use (second homes);

- dwellings leased to a diplomatic or consular mission of another country. This group of dwellings was usually occupied, but occupied by persons not covered by the census (enjoying diplomatic immunity). For this reason such dwellings were considered unoccupied;

- dwellings used exclusively for business activities.

Other  dwellings (H_OTH)
The census covered only those  dwellings which were not conventional dwellings but which were occupied for housing  purposes at the critical time of the census.
Occupied  dwellings which are not conventional dwellings are units which during the census - for different reasons, e.g. force majeure, adopted life-style - were the only place of residence of person(s) making up a household. They include:

- premises which are located in a permanent building (residential or other), built for other purposes than housing and which were not adapted to be used  for human habitation. They include e.g. attics, laundries, drying rooms,  garages, storerooms, buildings for livestock or utility buildings (stables, cowsheds, barns), or other (hotel rooms, classrooms).

- semi-permanent premises, built for housing of a family or an individual person, in principle for a limited period of time - usually a few years, They include e.g. 'containers' or shanties erected for persons affected by an extraordinary disaster (for flood or fire victims), as well as temporary buildings occupied until the new house is built;

- temporary premises, e.g.  shacks, cabins, huts;

- mobile units, e.g. crew wagons, railway wagons, caravans, yachts, houseboats.

Collective living quarters (CLQ)
Collective living quarters are  a set of premises (rooms and other ancillary units), located in one or several buildings, occupied by one, separate establishment,  which provide care and training services, or medical  care services, or hotel services, or other services, and which are usually occupied by large groups of individuals.
In some of these premises (establishments), persons live for a long period (from several months to several years), or permanently. Such establishments include, e.g., boarding schools, student houses, workers' hotels, orphanages, nursing homes for persons with chronic diseases and handicaps, monasteries, convents,
Homeless (HAR_HMLS)
Persons who, for different reasons (economic, family-related, or administrative reasons) declare absence of permanent residence. Persons who are deprived of a roof over their heads as a result of natural disasters (cataclysms, floods, fires, etc.) are not to be classified as homeless.

There are no particular reasons for data unreliability for this topic

Information on TFN was prepared on the basis of the  sample survey.
In accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009, using information on the family status and the number and age of children in a family, the following categories of families were specified:

1. Married couple families

a) without resident children;

b) with at least one resident child under 25;

c) with youngest resident son/daughter 25 or older;

2. Consensual union couple families (informal)

a) without resident children;

b) with at least one resident child under 25;

c) with youngest resident son/daughter 25 or older;

3. Lone father families

a) with at least one resident child under 25;

b) with youngest resident son/daughter 25 or older;

4. Lone mother families

a) with at least one resident child under 25;

b) with youngest resident son/daughter 25 or older;

Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided.

There are no particular reasons for data unreliability for this topic

Information on SFN was prepared on the basis of the  sample survey. In accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009, using information on the number of persons in the family, the following categories of families were specified:

1. 2 persons

2. 3 to 5 persons

a) 3 persons

b) 4 persons

c) 5 persons

3. 6 and more persons

a) 6 to 10 persons

- 6 persons

- 7 persons

- 8 persons

- 9 persons

- 10 persons

b) 11 and more persons

There are no particular reasons for data unreliability for this topic

Information on TPH was prepared on the basis of the  sample survey. In accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009, using information on household status, the number of persons in the household, and the number and ages of children in the family, the following categories of household were specified:

1. Non-family households

a) one-person households;

b) multiperson households.

2. One-family households

a) Married couple households;

- without resident children;

- with at least one resident child under 25;

- with youngest resident son/daughter 25 or older;

b) Consensual union couple households (informal)

- without resident children;

- with at least one resident child under 25;

- with youngest resident son/daughter 25 or older;

c) Lone father households

- with at least one resident child under 25;

- with youngest resident son/daughter 25 or older;

d) Lone mother households

- with at least one resident child under 25;

- with youngest resident son/daughter 25 or older;

Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided.

3. Two-or-more-family households

There are no particular reasons for data unreliability for this topic

Information on SPH was prepared on the basis of the  sample survey. In accordance with Commission Regulation (EC) No 1201/2009 of 30 November 2009, the following categories of households were specified, using information on the number of persons in the family:

1. 1 person

2. 2 persons

3. 3 to 5 persons

a) 3 persons

b) 4 persons

c) 5 persons

4. 6 and more persons

a) 6 to 10 persons

- 6 persons

- 7 persons

- 8 persons

- 9 persons

- 10 persons

b) 11 and more persons

There are no particular reasons for data unreliability for this topic

Information on SPH was prepared on the basis of the  sample survey. Information refers to the tenure status of the household under which one or more persons constituting a household occupied a given housing unit at the time of the census.
The following types of tenure status of households were specified during the census:

- a household with ownership right to a housing unit or a house. This applies to a household whose members occupy their own house or their own  dwelling (including households which earlier occupied a  dwelling on the basis of a co-operative right to the housing unit (either tenant's right, without the right to sell and without inheritance rights, or owner's right - with the right to sell and with inheritance rights). After the entry into force of the Act of 15 December 2000 on housing cooperatives, the right of separate ownership for such  dwellings was established (for one or several persons from the household) by means of an entry into the book of deeds;

- a household with co-operative right to the housing unit. This applies to a household which includes a member of a housing cooperative, who has the co-operative right to the housing unit. There is a further breakdown into a tenant's type co-operative right, or an owner's type co-operative right;

- a household living in a rented housing unit. This applies to a household which occupies a dwelling on the basis of a lease contract for the dwelling, signed with the owner of the dwelling or with the administrator of the building in which the dwelling is located (including temporary or social housing). This form can be found in all types of ownership of the dwelling, i.e. in dwellings owned by housing cooperatives, in dwellings which belong to  gminas, to the State Treasury, to  companies, to social housing associations, or to natural persons;

- a household  living in a sub-let housing unit . This applies in general to a second or third household occupying a dwelling as a lodger, i.e. a person paying rent for a room (or rooms) in a dwelling where there is already an enumerated household of a principal tenant - who either rents the dwelling, or is a member of a housing cooperative, or is the owner of the dwelling;

- a household occupying the dwelling as a result of being related to owner, or to the main tenant, or who occupies the dwelling on the basis of a residence entitlement valid for life;

- other types of tenure status. This category includes households occupying dwellings:

• in buildings owned by religious organisations;

• as a compensation for help  with household chores, e.g. for looking after the sick, or children, for or giving private tiution;

• as a compensation for work in an agricultural holding, or for work in another business run by the owner of the dwelling or the house;

• in housing which is provided as charity assistance for persons (families) who found themselves in a difficult housing situation, and who look after the dwellings in return for the assistance provided;

•without any legal title, as squatters.

On the basis of information regarding tenure status, households were broken down as follows:

- households of which at least one member is the owner of the housing unit. This category includes  households with right to ownership of a housing unit or a house, as well as those with a co-operative ownership  right to the housing unit;

- households of which at least one member is the  a tenant of all or a part of the housing unit. These include households with a cooperative (but not cooperative ownership) right to the housing unit , or which occupy it under a rental agreement or by renting from an existing tenant;

- households which occupy all or part of a  dwelling on the basis of another legal title or households which occupy  the  dwelling on the basis of being related to the owners, or under some other form of tenure.

There are no particular reasons for data unreliability for this topic.

Data processed under the topic TLQ are in accordance with the definition in Regulation 1201/2009. A living quarter is  housing which is the usual residence of one or more persons.  The terms "Conventional dwellings", "Other  dwellings" and "Collective living quarters" are defined as under the topic "Housing arrangements".

There are no particular reasons for data unreliability for this topic

The topic "Type of ownership" refers to the ownership of the dwelling and not to that of the land on which the dwelling stands.
In order to obtain information on the type of ownership as required by Commission Regulation (EC) No 1201/2009 of 30 November 2009, data on ownership of  dwellings were compared with tenure status of households obtained during the  sample survey.

"Owner-occupied dwellings" are those where at least one occupant of the dwelling owned the dwelling (ownership by natural persons).

Dwellings owned by natural persons were dwellings to which a natural person (or natural persons, e.g. spouses) have property rights. The  person concerned can be an owner of the entire real estate on which the dwelling is located, or have a share in a jointly-owned real estate, which is a right linked to the separate ownership of a dwelling, e.g. a dwelling located in a building where there is an association of owners of apartments . Property right to an entire real estate or to just a dwelling, with the attributed part of  the real estate (the share in the part jointly owned and used) should be disclosed in the book of deeds, and, in the absence of such book, in another document confirming ownership right.

"Cooperative ownership" refers to ownership within the framework of a housing cooperative. It applies to dwellings located in buildings owned or co-owned by a housing cooperative. There is a co-operative right of ownership of these dwellings, or tenancy type co-operative right. Excluded from this category were dwellings in respect of which, on the basis of the Act of 15 December 2000 on housing cooperatives, the right of separate ownership was established for one or several natural persons. Consequently, this type of ownership should apply to natural persons. On the other hand, this category includes tied accommodation, where dwellings owned by a housing cooperative are occupied on a tenancy basis by, e.g., a caretaker, or a technician performing maintenance work for the cooperative. These dwellings were classified under the category "housing cooperative".

"Rented dwellings" are those where at least one occupant pays a rent for the occupation of the dwelling, and where no occupant owns parts or the whole of the dwelling. These are dwellings occupied on the basis of a tenancy contract, or on the basis of an allocation of  tied accommodation (company apartment),  dwellings belonging to a  gmina, to  a company, to the State Treasury, or to a social housing  association.

Dwellings which belong to:

-  Gminas. They include  dwellings located in buildings which are wholly owned by  gminas, as well as those owned by  gminas but located in buildings which are joint-ownership real estate (where there is an association of owners of apartments), i.e.  dwellings which address the housing needs of all the  gmina’s population. This category also includes  dwellings which were handed over to the  gmina, but which are at the disposal of public utilities, such as: healthcare establishments, social assistance centres, educational establishments, cultural establishments, i.e.  dwellings which mainly address the housing needs of the staff working in these establishments. They also include  dwellings which were owned by the State Treasury but which were handed over to a  gmina in administrative receivership. This category also included dwellings owned by a poviat (local, poviat self-government), which were not owned by any of the  gminas, as well as dwellings which were owned by  gminas and were administered by a unit specially appointed to manage these housing resources (e.g. a Housing Administration Agency,  a Local Authority Houses Management).  They should not be identified with  dwelling stocks or this unit (see category " companies").

- State Treasury.  They include  dwellings:

• taken over (from former State farms (PGRs), which are part of the assets of the Agricultural Property Agency of the State Treasury;

• taken over and which are part of the assets of the  Military Housing Agency;

• administered by entities subordinated to: the Ministers of National Defence, Interior and Administration, Justice, as well as to the Head of the Internal Security Agency and the Intelligence Agency;

• administered by State authorities, State administration bodies, and State control bodies;

• given by an entity representing the State Treasury under a usufruct, lease or tenancy contract for use by diplomatic or consular missions of foreign States.

-  companies. They include  dwellings which belong to:

• State enterprises, as well as State organisational entities, e.g. research institutes, universities, artistic institutions;

• public utility companies, e.g. companies providing city transport, water and sewage systems, central heating supply etc., with the exception of housing administration agencies;

• private enterprises, operating as companies or cooperatives, with the exception of housing cooperatives.

- social housing associations.   Dwellings enumerated here are dwellings located in buildings owned by legal entities which in their names have the term "social housing associations", or an abbreviation "TBS", regardless of whether other entities ( gminas, housing cooperatives, work establishments) participated in the costs of construction of the building against rental of some  dwellings (on the basis of a tenancy agreement) to third persons indicated by these entities.

- other entities. This category includes  dwellings owned by institutions constructing for profit,  dwellings which are for sale. but not yet sold to natural persons, or which are for letting. It also includes  dwellings owned by religious organisations, associations, political parties, trade unions, etc.

There are no particular reasons for data unreliability for this topic

Data processed under the topic NOC are in compliance with the definition in Regulation 1201/2009.

There are no particular reasons for data unreliability for this topic

UFS categories were not used to present the size of  dwellings

There are no particular reasons for data unreliability for this topic

Data processed under the topic NOR are in compliance with the definition in Regulation 1201/2009.
Useful floor area of the housing unit is the sum of areas of all rooms within the housing unit, and in particular: bedrooms, living and dining rooms, kitchens (with window and without window), alcoves, pantries, entrance halls, halls, bathrooms, toilets, conservatories or porches, and other rooms which can be used for residential or auxiliary purposes by the dwellers, regardless of their intended and actual use.

Useful floor area of the housing unit also includes the surface of rooms which are used only for business purposes, i.e. those which were enumerated in the number of rooms, as well as the area of other spaces which were used for business purposes if there was no separate entrance to these rooms from the street, from a generally accessible courtyard, or from a generally accessible corridor.

The surface area of balconies, terraces and loggias, mezzanines, built-in wardrobes and cubbyholes, laundry rooms, drying rooms, attics, cellars and coal-holes, as well as the surface area of garages are not included in the useful floor space of the housing unit.

In village-type buildings, the surface area of the mudroom is usually included in the useful floor space of the housing unit. The mudroom was not considered to be a component of the housing unit and was not included in the useful floor space of the housing unit only when:

- the mudroom was the connection between the residential part of the building and the buildings for livestock or utility buildings;

- in addition to the mudroom, at the same floor level, there was an entrance hall;

- there was more than one housing unit in the building and the mudroom was used jointly as a commonly accessible corridor.

The space under the stairs in an individual building was included in the useful floor space of the housing unit when there was only one housing unit in the building. When there were two or more  dwellings, then the stairs and the space under the stairs was considered to be a common communication space.

In individual houses under construction, but already partially lived-in, only the surface area of rooms and auxiliary rooms which are finished was included in the useful floor space of the housing unit.

Data on the useful floor space of  dwellings originate from information given by occupants, on the basis of a declaration, or a voluntary presentation of documents, e.g. a tenancy contract, or a household charges booklet, or a plan of the individual house, or measurements of individual rooms (which are the components of the housing unit).

A room was defined as a space in a housing unit enclosed by walls separating it from other rooms and reaching from the floor to the ceiling or roof with direct daylight, of an area of at least 4 square metres.

"Rooms" are bedrooms, living rooms and dining rooms, as well as kitchens meeting the above-mentioned criteria. Other parts of a housing unit such as entrance hall, hall, bathroom, toilet, pantry, cubbyhole, built-in wardrobe, alcove, conservatory, porch, are auxiliary spaces and not considered to be “rooms”.

In the census, rooms proper and kitchens classified as rooms were enumerated separately. From a total number of rooms, rooms used exclusively for businesses purposes were enumerated separately. These were rooms which were used as premises of different companies, offices, legal firms, clinics, studios, workshops, enterprises, etc. These rooms were only enumerated when they were located within a housing unit and they had no separate entrance from the street, courtyard, or generally accessible corridor.

There are no particular reasons for data unreliability for this topic

No DFS categories were used to determine density standard.

There are no particular reasons for data unreliability for this topic.

Data processed under the topic DRM are in compliance with the definition in Regulation 1201/2009.
In order to determine density standard, the number of residential rooms (DRM) was taken into account, i.e. the number of rooms per occupant, excluding those used exclusively for business purposes.

There are no particular reasons for data unreliability for this topic.

A housing unit considered as having  a piped water installation is a housing unit inside which there is a tap with running water.

There are no particular reasons for data unreliability for this topic

Toilet facility is defined as a facility equipped with a flush toilet. The census only enumerated installations within the    dwellings from which the wastes are flushed by water from a flushing cistern, connected to a water supply system, regardless of whether this installation was located in a separate room (WC), or in a bathroom.

There are no particular reasons for data unreliability for this topic

Data processed under the topic BAT are in compliance with the definition in Regulation 1201/2009. A bathroom is a space in a dwelling in which a bathtub or a shower cabin, or both, are installed, together with equipment evacuating wastewater outside the building.

There are no particular reasons for data unreliability for this topic

Data processed under the topic TOH are in compliance with the definition in Regulation 1201/2009.
Central heating is defined as any installation providing heat (hot water, steam, or hot air) from a central source of heating to individual spaces in the housing unit.
At the next stage, centrally heated  dwellings were broken down, with regard to the source of energy, into the following subtotals:

- central heating from a network, enumerated when heating is provided from a heating plant, power plant, or local boiler rooms, or, alternatively, by using solar batteries (e.g. at the level of a cooperative), servicing more than one building;

- individual central heating, enumerated when the source of heating is located in a detached house (a central heaeting. boiler is installed in the house's own boiler room, or in another location, e.g. in the cellar, or if floor heating is installed), or if the source of heating is located in a multi-dwelling building (a so-called single-storey heating system), e.g. a c/h boiler is installed in the kitchen or in the bathroom.

There are no particular reasons for data unreliability for this topic

Data processed under the topic TOB are in compliance with the definition in Regulation 1201/2009.
Dwellings in residential buildings (both  detached houses and multi-dwelling buildings) and in non-residential buildings, were classified in respect of this characteristic.
A residential building was defined as a building intended for residential purposes, fully occupied by residential dwellings, as well as a building where, in addition to residential dwellings, there are also other premises, but where residential dwellings occupy at least half of the building. A non-residential building was defined as a building which is occupied more than 50% for non-residential purposes (for example it houses a school, an office, a store, a warehouse, a medical centre), in which at least one  dwelling may also be located.

There are no particular reasons for data unreliability for this topic

Data processed under the topic POC are in compliance with the definition in Regulation 1201/2009.
The topic "Dwellings by period of construction" refers to the year when the building in which the dwelling is located was completed, i.e. the year in which the building was commissioned. If a building was commissioned by parts (by entrances, by wings), the year in which the last part of the building was commissioned was considered to be the year of construction. For buildings rebuilt after a total destruction, the year of completion of rebuilding was considered to be the period of construction.

31/03/2014

Place of usual residence (GEO)
The adopted definition of the concept, as well as  the breakdowns,  ensure the comparability of results at the EU level.

Sex (SEX)
The adopted definition of the concept, as well as  the breakdowns,  ensure the comparability of results at the EU level.

Age (AGE)
The adopted definition of the concept, as well as the breakdowns,  ensure the comparability of results at the EU level.

Legal marital status/partnerships (LMS)
The adopted definition of the concept, as well as  the breakdowns,  ensure the comparability of results at the EU level. Information in the classification of the topic specified as optional, regarding same sex marriages/partnerships was not prepared.

Note: In the Polish census, information was obtained both for the legal marital status and  de facto marital status.

The legal position regarding marital status for persons aged 15 years and more was defined as marital status pursuant to the law in force in Poland (the Law on Civil Status Acts). Polish law allows marriages for women aged 16 and more and for men aged 18 and more.
Polish legislation does not provide for registered partnerships. Partnerships were determined on the basis of de factomarital status.
Pursuant to the provisions of the Act of 4 March 2010 on the Population and Housing Census in 2011 (Journal of Laws of 26 March 2010, No 47, item 277), an informal relationship means two persons living in the same household, who did not conclude marriage in the form provided for under the Polish law, but whose mutual relationships are of the conjugal nature.
Polish legislation does not allow same-sex marriages. As a result, no information was prepared in the Polish census on same-sex relationships, either for legal civil status or for  de facto marital  status.

Household status (HST)
The adopted definition of the concept, as well as  the breakdowns,  ensure the comparability of results at the EU level. Information specified as optional regarding the classification of the topic of same sex marriages/partnerships was not prepared.

Note: Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided.

Persons of not stated category living in a household - in the Polish census there are no persons included in that category (there are only persons within the family nucleus, or outside the family nucleus).
Persons of not stated category not living in a household - in the Polish census there are no persons included in that category (there are only persons living in a private household and not living in a private household, i.e. those living in collective living quarters and homeless persons).

Type of private household (TPH)
The adopted definition of the concept, as well as  the breakdowns,  ensure the comparability of results at the EU level.
No information specified as optional was prepared regarding the classification of the topic.  Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided. Neither was information prepared regarding households of same sex couples.

Size of private household (SPH)
Adopted definition of the term, as well as  the breakdowns  ensure the comparability of results at the EU level.

Family status (FST)
The adopted definition of the concept, as well as  the breakdowns, ensure the comparability of results at the EU level. No information specified as optional was prepared regarding the classification of the topic.
This family concept limits relationships between children and adults to direct (first-degree) relationships, that is between parents and children.
Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided. Neither was information prepared regarding same sex couples.
"Not stated" item - in the Polish census there are no persons included in that category (there are only persons with an established position in the family, or persons who do not form a family).
Not applicable - refers to persons who do not form a family nucleus.

Type of family nucleus (TFN)
The adopted definition of the concept, as well as  the breakdowns, ensure the comparability of results at the EU level. No information specified as optional was prepared regarding the classification of the topic.
Polish legislation does not provide for registered partnerships. As a result, no information regarding partners in registered partnerships was provided. Neither was information prepared regarding same sex couples.

Size of family nucleus (SFN)
The adopted definition of the concept, as well as  the breakdowns, ensure the comparability of results at the EU level.

Tenure status of household (TSH)
The adopted definition of the concept, as well as  the breakdowns, ensure the comparability of results at the EU level.

Current activity status (CAS)
The adopted definition of the concept, as well as  the breakdowns, ensure the comparability of results at the EU level.

Under the topic "Current activity status" (CAS)

- in group CAS.H2.4. "Homemakers and others", optional breakdown into categories 2.4.1 and 2.4.2 was not used

- additionally, category CAS.H 1.2.2. "Unemployed, previously in employment", included unemployed persons for whom no information was obtained as to whether they worked in the past (because of the absence of a separately code).

- category CAS.H 3.2. "Not stated" included persons residing in collective living quarters and homeless people.

Status in employment SIE.

The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

whereas:

- in group SIE. 4. Others ("Contributing family workers" and "Members of producers’ cooperatives") optional breakdown into 4.1 and 4.2 categories was not applied.

Occupation (OCC)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
Categories OCC.1. to OCC.10. of the breakdown "Occupation" list the 10 major groups of the ISCO-08 (COM) classification.

Industry (branch of economic activity) (IND)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
The categories IND.H.1. to IND.H.10.4. of the breakdown "Industry (branch of economic activity)" correspond to the 21 sections of the NACE Rev. 2 classification.

Location of place of work (LPW)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

whereas:

- in addition, in the codes: PL, PL1 - PL6, PL11- PL63 working persons were also included for which no information regarding their place of work was obtained, adopting the rule that "the Voivodeship of place of residence = the Voivodeship of place of work" (in view of the absence of a separate code for persons working whose place's of work location is not  determined).

Educational attainment (EDU)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Size of the locality (LOC)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Country/place of birth (POB)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
For this topic in the category glossary of countries 3.1 and 3.2. (optional) Information was prepared on the basis of declarations of persons concerned.

Country of citizenship (COC)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
As regards ‘Recognised Non-Citizens’ category, there is no such category in Poland.

Year of arrival in the country (YAE)
The adopted definition of the concept, as well as  the breakdowns, ensure the comparability of results at the EU level. Additional information was prepared for this topic, specified in category 2.1 and 2.2 as optional.

Place of usual residence one year prior to the census (ROY)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
In the Polish census information on the place of usual residence one year prior to the census was not obtained directly. The information was derived from the date of arrival to the place of current residence and the place of prior residence. If a person arrived to the place of current residence before 31 March 2010, it was assumed that that person resided in that locality a year prior to the census. If a person arrived after 31 March 2010, it was assumed that that person resided in that locality/country of previous residence a year prior to the census.

Housing arrangements (HAR)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Types of living quarters (TLQ)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Occupancy status of conventional dwellings  (OCS)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
In this topic data will not be provided in the category 'unoccupied conventional dwellings' 2.1 and 2.2 (optional categories).

Type of ownership (OWS)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Number of occupants (NOC)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Useful floor space and/or number of rooms of housing unit
Number of rooms (NOR)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
As it is possible to select a variable (based on Regulation No 519/2010) in the hypercube 41 (Number of all occupied conventional dwellings), variable UFS was presented at the level of Voivodeship, while variable NOR was prepared at the level 'total Poland'. In the hypercube 54 (Number of all occupied conventional dwellings), data for UFS were prepared at the level of sub-region, and for NOR at the level 'total Poland'.

Density standard (floor space– (DFS)
Density standard (number of rooms)– (DRM)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.
As it is possible to select a variable (based on Regulation No 519/2010) in the hypercube 41 (Number of all occupied conventional dwellings), variable DFS was presented at the level of Voivodeship, while variable DRM was prepared at the level 'total Poland'. In the hypercube 54 (Number of all occupied conventional dwellings), data for DFS were prepared at the level of sub-region, and for DRM at the level 'total Poland'.

Water supply system (WSS)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Toilet (TOI)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Bathroom (BAT)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Type of heating (TOH)
The adopted definition of the concept, as well as  the breakdowns,  ensure the comparability of results at the EU level.

Dwellings by type of building (TOB)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Dwellings by period of construction (POC)
The adopted definition of the concept, as well as the breakdowns, ensure the comparability of results at the EU level.

Figures provided by the National Statistical Institutes in the framework of the 2011 Population and Housing Census may differ from those transmitted in other statistical domains due to the cross domain differences in definitions and methodologies used.  For additional information please see metadata specific to each domain.

Internal coherence is assured by regulations defining breakdowns and definitions of topics (Regulation (EC) No 1201/2009, Regulation (EU) No 519/2010, Regulation (EU) No 1151/2010)

The Population and Housing Census carried out in 2011 differed considerably from the 2002 Census Round   in the majority of areas which have an impact on the procedures governing individual census tasks and their financing. The organisational breakdown of census offices into a Central Census Office and Voivodeship and  Gmina Census Offices remained roughly the same. However, tasks performed by these offices and the number of staff assigned to them were adapted to the new operational formula of the census in 2011.
In 2011 census, data from administrative sources and from non-administrative systems were extensively used (both at the stage of preparatory work and through the initial completing of census forms). At the same time, paper forms were completely abandoned and replaced by IT solutions. For the first time, GIS solutions were used at each stage of the census. The 2011 census was performed using a  full-scope survey method on 80% of the population, collecting information on a short form, combined with the representative method on 20% of the population (taking into account communes inhabited by national and ethnic minorities). In the latter case, information was collected on a long form, in which questions are a more detailed version of issues included in the short form. In the 2011 census respondents were given a possibility to choose the way in which they wanted to provide answers. They could opt for Internet-based self-enumeration (CAWI method), by way of responding to telephone surveying by a statistical interviewer (CATI method), or by answering census enumerators directly (CAPI method).
Regardless of the method of performance of censuses, essential objectives (obtaining information regarding population and  dwellings, processing the results and making them available) were achieved. What remained to be done was to carry out an analysis and to answer the question of what impact the changes in methodology and organisational solutions had on the costs of the census.

Census costs according to the UN
Official conclusions drawn by the UN  regarding costs of the 2000 round  of censuses, broken down by methods of implementation, indicate that:

- for the group of countries which opted for a traditional method of census enumeration (Poland belongs to that group), the average census cost per capita was 2.1 nominal USD, and when counted using PPP method (Purchasing Power Parity) it amounted to 5.2 PPP USDs;

- compared to the average result in the group, indicators for Poland were respectively: 3.8 nominal USDs and 8.5 PPP USDs.

Calculation of census costs for the 2010 census round was done in the same manner. This time Poland was in the group of countries which opted for a mixed method of census enumeration (3 groups were specified: Traditional Census, Mixed Census, and census based on AdministrativeRegisters). In that group:

- the average value of census cost per capita was 3.94 nominal USD, and 6.01 PPP USD.

- compared to the average result in the group, indicators for Poland were respectively: 3.54 nominal USDs and 5.59 PPP USDs.

The above-mentioned data indicate that the Polish traditional census in 2002 was expensive not only taking into account the relationship between 2002 and 2011 costs, but also when compared with other countries, it considerably exceeded average values for the group.
On the other hand, in 2011 not only were considerable savings made, but Poland also obtained a very good rating against other countries, ending up below average values in the group. It is very likely that this situation is not only the result of using registers data, but is also helped by the fact of using the  sample survey, and less expensive methods of data collection for the subjects for which it was not possible to use registers data.

Additional national indicators
The costs of NSP 2011 was calculated on the assumption of it being carried out using the traditional method, precisely as the 2002 census was carried out. Two calculation methods were used with the following results:

• future value method using the reference rate of NBP (the National Bank of Poland) of 6.75%: 6.28 nominal USDs per capita;

• method of calculation according to the average wage increase index between 2002 and 2010: 6.17 nominal USDs per capita.

Thus, census costs if the traditional method had been used would have been much higher if costs actually incurred using current organisational and methodological solutions.
Despite changes in the methodology of the census, the collection of data remained the most cost-intensive part of the census. The most significant differences in the costs of the 2002 and 2011 censuses which, at the same time, demonstrate the cost-effectiveness of the 2011 census, can be observed in the following groups of expenditures. These calculations were confirmed by an audit carried out by Deloitte.

Forms in 2011
Not a single form was printed for use in NSP 2011. All the work of census enumerators was supported by a mobile application in which an electronic form was available. Data transmission between mobile terminals and census infrastructure was carried out on the basis of a mobile network, within which a safe, dedicated access point APN was created, to which mobile terminals were linked. As a result, a census enumerator did not carry completed forms. In addition, to facilitate the Internet-based self-enumeration, a specially developed form was made available online.   For comparison purposes, in 2002 the contractor selected through tendering procedure supplied in excess of 16 million housing  forms on paper, close to 49 million personal  forms on  paper, just under 8 million paper forms to examine long-term migration, and approximately 0.5 million paper forms to examine the fertility rate of women. The cost of purchasing mobile terminals for NSP 2011 was PLN 16 878 998.97, while costs for the NSP 2002 census, covering the purchase of paper, the printing of census forms, delivery of forms to census  enumerators and storage of forms  amounted in 2002 to PLN  20 214 467. After scanning, forms were destroyed. Mobile terminals purchased for censuses continue to be used by statistical interviewers in current surveys.

Number of census enumerators in 2011
Approximately 21 thousand persons received relevant training prior to the 2011 census. 18 thousand census enumerators carried out the census. In 2002 close to 210 thousand persons received relevant training and 161 thousand census enumerators carried out the census. Remuneration of census enumerators only, together with employer's charges amounted to PLN 97 819 116.16, and when the costs of statistical interviewers are added, it amounted to PLN 103 381 350.75. In 2002 this amount was PLN 250 956 114.

Census organisation structure
A three-level census organisation structure was used during the 2002 census and during the 2011 census. It included census offices in the Central Statistical Office (CSO) , census offices in Voivodeships, and census offices in  gmina.
Modification of structures, including the number of persons involved in census work for the 2011 census was mainly the result of the implementation of modern technologies, as well as the modified methodological approach to the performance of the census (e.g. 20% of the population was included in the enumeration carried out by census  enumerators.
During the NSP 2002, 26 100 persons were involved in census work at the level of  gmina (communal/municipal census offices and branches thereof). They worked in 2 489  gmina census offices and in 570 branches.
During the NSP 2011,  gmina census offices were established in 2 479  gminas, employing approximately 6 000 persons on census work. Out of this number, more than 2 800 persons played the role of  gmina leaders. Costs incurred in respect of these persons in 2002 were PLN 90 348 552.75 and in 2011 PLN 77 784 584.19.

Not envisaged

Primary data sources for the Population and Housing Census in 2011 (NSP 2011) on persons were administrative registers - register based data sources and data from IT systems - as well as data gathered directly from the population, during a  sample survey carried out on a 20% sample (on national scale) of persons living or residing in  dwellings randomly drawn (questionnaire based data sources).
In NSP 2011, in order to prepare information regarding the status and structure of population (as regards basic breakdowns, i.e. sex, age, residence), data from population registers were used (i.e. PESEL register -, as well as gminas (municipal) registration records), and data from information systems kept by tax authorities and insurance systems, on the basis of which reference population was established.

A primary data source in the  Population and Housing Census in 2011 (NSP 2011) on households was a  sample survey carried out on a 20% sample (on national scale) of persons living or residing in  dwellings randomly drawn (questionnaire-based data sources).

A primary data source on family nuclei in the Population and Housing Census in 2011 (NSP 2011) was a  sample survey carried out on a 20% sample (on national scale) of persons living or residing in  dwellings randomly drawn (questionnaire-based data sources).

A primary data sources on conventional dwellings for the Population and Housing Census in 2011 (NSP 2011) was a  sample survey carried out on a 20% sample (on national scale), and information originating from information systems of the public administration.

A primary data sources on living quarters for the Population and Housing Census in 2011 (NSP 2011) were data obtained from administrative sources - registers and information systems (register-based data sources). First, administrative data were used, i.e. the National Register of the Official Territorial Division of the country (TERYT). Other data used were data collected in the so-called buildings database, created for the census, on the basis of data originating from current reporting, as well as from a one-off survey, carried out to update data for multi-dwelling buildings.

Data on population and housing censuses are collected every decade, in a reference year that falls during the beginning of every decade

An electronic platform was created to be used during the census, containing systems, subsystems, and applications which supported collecting, processing, and disseminating census data. The architecture thus prepared contained an Operational Microdata Base (OMB), an Analytical Microdata Base (ABM), as well asa  Metainformation Subsystem, systems supporting the servicing of different data collection channels (CAxI), and an application for the management of completeness of the census ().
A list of census subjects - in the form of an electronic list of dwellings with addresses - was created on the basis of an official, territorial statistical register, the geodetic and cartographic resource, and  gmina residence registration data. This list was verified by census enumerators during a pre-census field check.
Information to be collected during the census was gathered primarily from administrative sources. 28 out of 300 examined registers were used. Data from administrative sources were initially entered into on-line census forms.  Missing data were collected on on-line forms from persons covered by the census. CAxI (CAWI, CATI, CAPI) methods were used. Forms were prepared on-line. In addition, the form for the full – scope survey was also prepared on-line. Forms were prepared as an application for mobile, hand-held equipment, as well as in the Internet version which was used during the self-enumeration and during the telephone surveying (CATI).   Separate, simplified electronic forms were used for homeless persons and for persons residing in collective living quarters. An appropriate form-dedicated application verified whether the form was correctly completed. This involved, i.a., logical and computing checking. During the census, data introduced into the electronic form were encrypted, and after the form was completed, data were sent to the Central Statistical Office (CSO) server. Both during the pre-census field check and during the census, census enumerators used mobile terminals equipped with an application which made it possible to use digital maps in the field work. Infoline was activated for respondents using the CAWI method.

The following surveys were carried out during the census:

- a full - scope survey for the whole population (form - 16 questions)

- a  sample survey for a sample of 20% of the population (form - 100 questions)

- a survey of persons residing in collective living quarters

- a survey of homeless persons

The first data collection channel was the Internet-based self-enumeration (CAWI), where respondents could verify data obtained by CSO from registers. Respondents could correct data and add missing information. Persons doing self-enumeration via the Internet, having introduced their log-in and password on the CSO website, could access the form for a given household. The validation of respondents was done on the basis of data obtained from administrative registers. Following the introduction of a data combination, a password was generated for the user which made it possible to log-in to the self-enumeration portal.
The next channels, introduced in parallel, were CATI and CAPI.
To inform the public about the census, its organisation, timetable, and the method of participation, a promotional campaign was organised, addressed to different social groups. The most important role in the implementation of the programme was played by public media, who were required by the legislator to include in their programmes, free of charge, broadcasts promoting the census.

Validation applied to datasets regarding population and  dwellings, as well as buildings. It consisted of the updating of the relevant list of  dwellings with addresses at the critical moment. As a result, "a dataset of persons to be enumerated" was created. For these persons, a Golden Record was established with census data.
Tables from the  dwellings register with addresses were linked with data from the national population register PESEL (PIN-Personal Identification Number) which was additionally obtained after the enumeration was completed. The objective was to establish what the population of persons was on 31 March 2011, by verifying the list and adding persons who were registered on the PESEL register by 31 March 2011 and were not included on the  dwellings register established before the census.

The following procedures were used:

1. The following data were aligned:

- data on persons - based on the  dwellings register after the census - who had a PESEL numbers at the critical moment; information was added regarding children under one year of age without a PESEL number, regarding foreigners without the PESEL number, and regarding other persons without a PESEL number;

- individual datasets from the registration of demographic facts valid at the time, regarding deaths and live births were compared with the dataset of persons from the above-mentioned housing register.

2. Records regarding persons of 90+ without a current address of residence, or not residing in the country, were verified.

Validation procedures for dwellings and buildings:

1. Analysis from the point of view of records with information not stated.

2. A comparison of data with information obtained in current statistical surveys carried out in the field of housing management and  gmina infastructure, and with results obtained during the NSP 2002.

Processing of data obtained in the 2011 Population and Housing Census was done in the Operational Microdata Base (OBM) for personalised data, and in the Analytical Microdata Base (ABM) for anonymised data.
Collection and processing of data from administrative registers and systems, as well as from census forms, was done in the OBM, which contained personalised data on the census unit, together with the value of characteristics obtained from administrative sources and from direct interviews, as well as those obtained as a result of self-enumeration.
Operations carried out within the OBM included the preparation of the checklist for the pre-census field check, preparation of data to fill out forms electronic CAxI, based on data from administrative registers. Under the control of these systems, during interviews, census questionnaires were filled with data and subsequently verified. Verification included correctness of answers given and logical and arithmetic control. Once data of satisfactory quality has been collected, datasets with census data were returned to OBM, where, after reading, together with data from other sources, they were used for elaboration of the final census results.

The ETL processes model was implemented in the OBM through the following subsystems:

- loading of lists

- import, cleaning, integration and verification of data

- storage of census data

- servicing the census frame

- servicing  CAxI

- correcting data

- data processing

- generating operational reports

- export of data (Golden Record) to ABM

The Golden Record (GR) contains all variables collected for the census and originating from different channels. The GR has a structure of interrelated tables (Buildings, Dwellings, Collective Living Quarters, Homeless Persons, Emigrants, Households, Families). Cross tabulation was done via identifiers (ID).
The scope of information in the GR included variables which could be directly  derived (so-called primary variables), and secondary variables which were derived from auxiliary variables, or primary variables.
Census variables were calculated on the basis of defined algorithms indicating the origin of variables as well as mathematical and logical rules used for their calculation.  Output of GR characteristics was a continuous process. During subsequent iterations of GR generation, characteristics were modified, i.e. new characteristics would appear and the existing ones would be updated through the verification of algorithm, e.g. by including new elements of logical control. Some of the characteristics could also be eliminated.
Following depersonalisation of the GR and after a Unique Statistical Number (USN) was assigned to a person, making it possible to compile data, further processing of data took place in the ABM. The following groups of processes can be distinguished in the ABM:

1) Data processing

- data and metadata loading

- data integration

- data classification and coding

- data validation and editing

- creation of secondary data or of new statistical units

- weighing of results of a  sample survey

- calibration of weights

- Data Analysis

2) Dissemination of data

In view of the functionality of the ABM, secondary variables were calculated there (on the basis of primary variables), as well as secondary objects (households and families).
The next stage was the generalisation of results of the  sample survey.
Following this process, internal users performed the analysis, assessed the correctness of results obtained and accepted variables calculated in the GR. The next process was the preparation of data for dissemination.