Acquisition and loss of citizenship (migr_acqn)

Reference Metadata in Euro SDMX Metadata Structure (ESMS)

Compiling agency: Eurostat, the statistical office of the European Union

Eurostat metadata
Reference metadata
1. Contact
2. Metadata update
3. Statistical presentation
4. Unit of measure
5. Reference Period
6. Institutional Mandate
7. Confidentiality
8. Release policy
9. Frequency of dissemination
10. Accessibility and clarity
11. Quality management
12. Relevance
13. Accuracy
14. Timeliness and punctuality
15. Coherence and comparability
16. Cost and Burden
17. Data revision
18. Statistical processing
19. Comment
Related Metadata
Annexes (including footnotes)

For any question on data and metadata, please contact: EUROPEAN STATISTICAL DATA SUPPORT


1. Contact Top
1.1. Contact organisation

Eurostat, the statistical office of the European Union

1.2. Contact organisation unit

F2: Population and Migration

1.5. Contact mail address

2920 Luxembourg LUXEMBOURG

2. Metadata update Top
2.1. Metadata last certified 06/03/2019
2.2. Metadata last posted 06/03/2019
2.3. Metadata last update 06/03/2019

3. Statistical presentation Top
3.1. Data description

Eurostat's annual collection of statistics on acquisitions of citizenship flows is structured as follows:


Data Collection

Info & Legislation

Unified Demographic

The most in-depth annual national and regional data collection on demography and migration, for population, births, deaths, immigrants, emigrants, acquisition and loss of citizenship, marriages and divorces by a large number of breakdowns. (Article 3 of Regulation (EU) No 1260/2013 and Article 3 of Regulation (EC) No 862/2007).


The aim is to collect annual mandatory and voluntary data from the national statistical institutes. Mandatory data are those defined by the legislation listed under ‘6.1. Institutional mandate — legal acts and other agreements’.

The quality of the demographic data collected on a voluntary basis depends on the availability and quality of information provided by the national statistical institutes.

For more information on mandatory/voluntary data collection, see 6.1. Institutional mandate — legal acts and other agreements.


The following data on acquisition and loss of citizenship are collected:

  • Acquisitions of  citizenship by age, sex and former citizenship
  • Loss of citizenship by sex and new citizenship


Naturalisation rates: based on the different breakdowns of data received on acquisition of citizenship and migrant populations, Eurostat produces the following statistics (migr_acqs):

                 a.   share of foreign citizens who have acquired citizenship
                 b.   share of EU citizens who have acquired citizenship
                 c.   share of  non-EU citizens who have acquired citizenship

3.2. Classification system

For GEO (reporting country) and  CITIZEN (citizenship) classifications the two-letter ISO (International Organisation for Standardisation) 3166 alpha-2 code is used, except for Greece and the United Kingdom for which the abbreviations EL and UK are used.

3.3. Coverage - sector

Not applicable

3.4. Statistical concepts and definitions

Citizenship means the particular legal bond between an individual and his or her state, acquired through birth or naturalisation, whether by declaration, choice, marriage or other means according to national legislation.

Naturalisation is one of the most common ways of acquiring citizenship. It is a formal act of granting citizenship to an alien who applies to be a citizen. International law does not set out detailed rules on naturalisation, but recognises the competence of every state to naturalise non-nationals.

Generally, a period of legally registered residence is required, combined with other criteria such as evidence of social and economic integration and knowledge of national languages. Different criteria may apply for people born or educated in the country concerned, or who have parents or other relatives with that country’s citizenship.

Stateless: A stateless person is not considered as a national by any State under the operation of its law, as set out in article 1 of the 1954 Convention relating to the status of stateless persons.

Recognised non-citizens: Persons who are not citizens of the reporting country, nor of any other country, but who have established links to the reporting country, which include some but not all of the rights and obligations of full citizenship. This category consists mainly of former Soviet citizens living in the Baltic States who have not applied for the citizenship of their current country of usual residence.

Age reached: at the end of the year.

Age completed: on the person’s last birthday.

Historical age definition of acquisitions of citizenship statistics under Article 3 Regulation (EC) 862/2007

Note : R (age Reached); C (age Completed); B (Both age reached and age completed)

Albania, Montenegro, The former Yugoslav Republic of Macedonia, Serbia, Turkey, Andorra, Armenia, Azerbaijan, Republic of Bosnia and Herzegovina, Belarus, Georgia, Monaco, Republic of Moldova, Russian Federation, San Marino, Ukraine and Kosovo (under UNSCR 1244) are not included in the analysis because their data are not disseminated online from 2008 onwards due to definitional problems.

Share of foreign citizens who have acquired citizenship: defined as the number of foreign citizens resident in each EU Member State who acquired citizenship of that Member State during the calendar year , as a share of the total number of resident foreigners at the beginning of the year

Share of EU citizens who have acquired citizenship: defined as the number of  another EU citizens resident in each EU Member State who acquired citizenship of that Member State during the calendar year , as a share of the total number of another EU citizens residents at the beginning of the year

Share of non-EU citizens who have acquired citizenship: defined as the number of  Non- EU citizens (including stateless) resident in each EU Member State who acquired citizenship of that Member State during the calendar year, as a share of the total number of Non- EU citizens residents at the beginning of the year

Level of development: the relative degree of development of a country as defined by statistical measures of three basis dimensions - health, education and standard of living. The list of countries and citizenships to be included in each groups by level of development is given in Annexes.

3.5. Statistical unit

The statistical unit used is ‘number’ as indicated in the online database or by the titles of tables.

3.6. Statistical population

The statistical population is the total population. For more information on the population concepts used, see the population reference metadata (demo_pop).

3.7. Reference area

The acquisition of citizenship statistics are disseminated by single country as follows:

a) Member States of the European Union

b) EU candidate countries

c) EFTA countries

d) Other countries: Andorra, Armenia, Azerbaijan, Belarus, Bosnia and Herzegovina, Georgia, Moldova, the Russian Federation, San Marino, Kosovo (under UNSCR 1244) and Ukraine.

3.8. Coverage - Time

The available time series collected and published in the Eurostat database varies, depending on the acquisition of citizenship breakdowns, with the longest time series starting in 1998 by totals, in 2002 by former citizenship and  in 2008 by age, sex and former citizenship. Data on loss of citizenship are available from 2008 onwards.

The completeness of the time series of the acquisition of citizenship statistics collected on a voluntary basis before the regulations listed under 6.1 Institutional mandate — legal acts and other agreements’ entered into force,and of the loss of citizenship statistics that continue to be supplied to Eurostat on a voluntary basis depends on the availability of data from the national statistical institutes.

3.9. Base period

Not applicable

4. Unit of measure Top

Data on acquisitions/losses of citizenship are disseminated in integer numbers.

5. Reference Period Top

The reference period for acquisitions/losses of citizenship flow data is the calendar year in which the acquisition/loss of citizenship occurred.

6. Institutional Mandate Top
6.1. Institutional Mandate - legal acts and other agreements


Regulation (EC) No 862/2007 of the European Parliament  and of the Council of 11 July 2007 on Community statistics on migration and international protection and repealing Council Regulation (EEC) No 311/76 on the compilation of statistics on foreign workers.

Commission Implementing Regulation (EU) No 351/2010  as regards the definitions of the categories of the groups of country of birth, groups of country of previous usual residence, groups of country of next usual residence and groups of citizenship with 1 January of the reference year as reference time for the composition of the list of countries to be included in each of the groups. However, given Regulation (EU) 1260/2013 on European demographic statistics had entered into force and for the sake of consistency, it was decided by gentlemen’s agreement to take the end of the reference year as the reference date and to exclude stateless people from the category of non-EU nationals.

Data for the 2013 onwards therefore include Croatia, which joined the EU on 1 July 2013, in the EU aggregates. Non-EU citizens are defined as those who do not have the citizenship of any of the 28 EU-28, excluding stateless people. However, data for 2012 backwards exclude Croatia from the EU aggregates. Non-EU citizens are those who do not have the citizenship of any of the 27 EU Member States, including stateless people.



For the series listed in ‘3.1. Data description’, data collected on a voluntary basis relate to:

  • acquisitions of citizenship by former citizenship before reference year 2008
  • losses of citizenship by sex and new citizenship since reference year 2008
6.2. Institutional Mandate - data sharing

Not applicable.

7. Confidentiality Top
7.1. Confidentiality - policy

Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009  stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and access to those confidential data with due account for technical developments and the requirements of users in a democratic society and Amending Regulation (EU) No 2015/759 of 29 April 2015 as regards the violation of statistical confidentiality.

7.2. Confidentiality - data treatment

Not applicable

8. Release policy Top
8.1. Release calendar
Calendar Data collection
March T+1

Acquisitions of citizenship flows by age, sex and former citizenship for reference year T-1

Losses of citizenship flows by sex and new citizenship for reference year T-1


  • Acquisition/loss of citizenship data refer to acquisitions and losses during the reference period of one calendar year T-1, from 1 January until 31 December of that year.
  • Acquisition/loss of citizenship data are collected by Eurostat annually by 31 December of year T.
  • Acquisition/loss of citizenship data are disseminated by Eurostat annually by March of year T+1.


Eurostat disseminates online revisions of data (from provisional to definite data, for example) as soon as data are transmitted. As a consequence, the date of the table online can differ from March T+1

8.2. Release calendar access

Not available.

8.3. Release policy - user access

In line with the Community legal framework and the European Statistics Code of Practice Eurostat disseminates European statistics on its website (see item 10 - ‘Accessibility and clarity’) regarding professional independence, in an objective, professional and transparent manner in which all users are treated fairly. The detailed arrangements are governed by the Eurostat protocol on impartial access to Eurostat data for users.

9. Frequency of dissemination Top

The national statistical institutes continuously revise acquisition/loss of citizenship statistics according to the most recent data released, before transmitting them to Eurostat.

Data are disseminated in line with the 8.1 Release calendar and with 17.1 Data revision policy.

10. Accessibility and clarity Top
10.1. Dissemination format - News release

News releases on-line.

10.2. Dissemination format - Publications

Statistics Explained articles on Eurostat website: Acquisitions of citizenship statistics

Eurostat interactive infographic on acquisition of citizenship in the EU

Eurostat Yearbook

Domain specific publications

10.3. Dissemination format - online database

 Eurostat’s Data Navigation Tree.

10.4. Dissemination format - microdata access

Not applicable

10.5. Dissemination format - other

Not applicable.

10.6. Documentation on methodology

There is more information on methodology by country in the annexes.

10.7. Quality management - documentation

Not available.

11. Quality management Top
11.1. Quality assurance

Quality assurance is part of data processing. Statistical products and processes are systematically reviewed in accordance with the Quality Assurance Framework of the European Statistical System since 2008.

11.2. Quality management - assessment

Article 12 of Regulation (EC) No 862/2007 states that the Commission shall submit reports on its implementation to the European Parliament and the Council as follows:

- first report by August 2012

- second report by August 2015

- every 3 years thereafter. Next report by August 2018.


These reports evaluate the quality of the data Member States and EFTA countries send to Eurostat and the data collection methods used. If appropriate, the reports should be accompanied by proposals to improve the legal framework for migration statistics under this Regulation.

12. Relevance Top
12.1. Relevance - User Needs

Citizenship acquisition statistics are widely used for planning actions and monitoring and evaluating programmes in a number of social and economic policy areas. These include:

  • evaluating the economic, social and environmental impact of foreign demographic change;
  • key input for studying the background of new EU citizens;
  • contributing to the study of foreign population trends in Europe;
  • core indicators of the integration of foreign citizens;
  • measuring the effect of national policies on citizenship.


Citizenship acquisition trends and developments have a big impact on the societies of individual countries and the EU. Statistics on the 'size and structure of and changes in Europe’s population are used in a wide range of policy areas.

12.2. Relevance - User Satisfaction

No user satisfaction surveys have been carried out.

12.3. Completeness

Data completeness depends on the availability of data from the national statistical institutes.

13. Accuracy Top
13.1. Accuracy - overall

 Not available.

13.2. Sampling error

 Not applicable.

13.3. Non-sampling error

Not applicable.

14. Timeliness and punctuality Top
14.1. Timeliness

For the timeliness of data release see 8.1 Release calendar.

14.2. Punctuality

 Not applicable.

15. Coherence and comparability Top
15.1. Comparability - geographical

The recommended definition of population, in line with Regulation (EC) No 862/2007, is the ‘usually resident population’, meaning all the people usually resident in a Member State on the reference date. On the basis of this definition, the following people alone are considered usual residents of the geographical area in question: those who have lived in their place of usual residence continuously for at least 12 months before the reference date or those who arrived in their place of usual residence during the 12 months before the reference date with the intention of staying there for at least 1 year. If the circumstances described above cannot be established, ‘usual residence’ can be taken to mean the place of legal or registered residence.


According to Regulation (EC) No 862/2007, when national statistical institutes send citizenship acquisition statistics to Eurostat, they should use the same definition as the one used for population. For example, if population is defined according to usual residence, the number of acquisitions of citizenship should be of those who establish their usual residence in the territory of a Member State for a period that is, or is expected to be, at least 12 months, having previously been usually resident in another Member State or a non-EU country.


The metadata information provided by the countries in question confirms that citizenship acquisition statistics are compiled according to the harmonised definition mentioned above.


Countries by definition of acquisitions of citizenship

Acquisitions of citizenship by people living in the country




Note: The national statistical definition of citizenship acquisition of UK included some people not living in the country, but the impact is considered negligible.

15.2. Comparability - over time

Breaks in data series could compromise comparability over time. The breaks in citizenship acquisition series due to methodological changes, data processing changes or revisions in acquisitions counts reported by the countries in question are documented in Eurostat’s database with the flag b (break in series).

The reason the citizenship acquisition/loss of citizenship flows data available between reference years 2008 and 2009 is flagged as a break in the series is a change in production methods, described as a first shift from the national definition to the harmonised definition of those usually resident in the territory of the country in question.

Improvements in and changes to the administrative systems and statistical methodology may also cause breaks in the time series.

There is more information on methodology by country in the annexes.

15.3. Coherence - cross domain

 Not applicable.

15.4. Coherence - internal

Statistical or other adjustments could be needed to calculate the demographic balancing equation for the non-national population due to statistical inaccuracies or methodological differences in calculating the equation. See the fertility (demo_fer), mortality (demo_mor), population (demo_pop) and migration (migr_immi and migr_emi) reference metadata.

- Non-national population of the previous year plus non-national live births, minus non-national deaths plus non-national immigrants minus non-national emigrants, minus acquisitions of citizenship plus losses of citizenship equals the non-national population on 1 January of the year in question.

16. Cost and Burden Top

Not applicable.

17. Data revision Top
17.1. Data revision - policy

The policy of Eurostat is to update the information it provides as soon as data are received and at any time during the year.

17.2. Data revision - practice

Citizenship acquisition/loss of citizenship statistics are continuously revised according to the most recent data released and sent to Eurostat by the national statistical institutes.

The status of the data is indicated by using flags (p = provisional data; e = estimated; b = break in time series).

18. Statistical processing Top
18.1. Source data

Eurostat collects data from the national statistical institutes.

The table below shows the sources of citizenship/loss of citizenship statistics declared by the national statistical institutes:

18.2. Frequency of data collection

Data are collected annually.

18.3. Data collection

National statistical institutes collect the statistics and send them to Eurostat. Data are requested from national statistical institutes as part of the unified demographic data collection. The unified demographic data collection contains both mandatory and voluntary data (see section 3.1. Data description).

18.4. Data validation

The validation checks carried out on raw data sent to Eurostat by the national statistical institutes are either checks of internal consistency within each table, or checks of external consistency between different tables reporting the same data differently disaggregated.

Eurostat also asks data providers to supply specific metadata describing the definitions used and the quality of the statistical outputs to assess uniform standards. To ensure the consistency and comparability of the statistics produced, Eurostat checks if the data it receives are consistent internally and over time, and if they are in line with the principles of the European Statistics Code of Practice and Regulation (EC) No 223/2009 on European statistics.

For more information on data validation by Eurostat see

18.5. Data compilation

Geographical aggregation

Eurostat disseminates geographical EU aggregates on acquisitions of citizenship flows by applying a common arithmetical sum of the flows of the EU Member States on the Eurostat website. However, the EU aggregates for the period 2010-2012 include 2009 data for Romania.


Residents who acquired citizenship as a share of resident non-citizens by former citizenship and sex

The share of immigrants that have acquired citizenship was selected as one of the 14 core indicators of immigrant integration in the EU (Zaragoza Declaration). Since this indicator was developed in a general way, Eurostat decided to publish the naturalisation rate, defined as the number of foreign citizens resident in each EU Member State who acquired citizenship of that Member State during the calendar year, as a share of the total number of resident foreigners at the beginning of the year. The naturalisation rate should be used with caution. This is because the numerator includes all modes of acquisition, not just naturalisations of eligible resident foreigners, and the denominator includes all foreigners, not the relevant population, i.e. foreigners who are eligible for naturalisation.


It is calculated for men, women and both sexes combined, and for EU and non-EU citizens.


being  the number of acquisitions of citizenship of the reporting country in the year t by persons of sex s and former citizenship c (EU / non-EU), and  the corresponding foreign population at the beginning of the period. By construction, it is therefore rather a probability than an occurrence-exposure rate, but it is now commonly named 'rate'.


In fact, for EU citizens other than the reporting Member State:


and for non-EU citizens, including stateless:


For more information on measuring migrant integration see

18.6. Adjustment

Not applicable.

19. Comment Top

Not applicable.

Related metadata Top

Annexes Top
National Metadata Reports - 2008 Acquisition and loss of citizenship data
Additional information - EU funded THESIM project (2005) - Acquisition of citizenship
Methodology by country
The country of citizenship classification used by Eurostat based on UN HDI for 2013
Annex - Acquisition of citizenship data until 2008