National Statistical Institute of Bulgaria

“Science, innovation and information society” department

2, Panayot Volov str., Sofia 1038, Bulgaria

The EU survey on the use of ICT in households and by individuals is an annual survey conducted since 2002. In Bulgaria, it has been conducted since 2004 (except for 2005).

In 2022, the survey collects data on the access to information and communication technologies (ICT), on the use of the internet, e-government, e-commerce, internet of things, as well as green ICT.

National language: Изследване за използването на информационни и комуникационни технологии в домакинствата и от лицата през 2022 година

English: Survey on the use of ICT in households and by individuals 2022

Questionnaire(s) in national language(s) and the translation in English are available in the annex.

The following common concepts and definitions apply under the Integrated European Social Statistics (IESS):

• the International Standard Classification of Education (ISCED) 2011 published in the following breakdowns: low (ISCED levels 0-2: no formal education, primary education or lower secondary education), medium (ISCED levels 3-4: upper secondary or post-secondary non-tertiary education) and high (ISCED levels 5-6: tertiary programmes which normally need a successful completion of ISCED 3 or 4, or second-stage tertiary education leading to an advanced research qualification);
• the International Standard Classification for Occupation ISCO-08 at the 2-digit level;
• the Classification of Economic Activities (NACE Rev.2-2008), at section level;
• the Common classification of territorial units for statistics (NUTS 1) – finer granularity of NUTS 2 is provided on optional basis by some Member states;
• the SCL - Geographical code list;
• information about household income is provided at lower level of detail. 

Additional classifications used in the national questionnaire: No additional classifications are used in the national questionnaire.

The ICT survey in households and by individuals covers those households having at least one member in the age group 16 to 74 years old. Internet access of households refers to the percentage of households that have an internet access, so that anyone in the household could use the internet.

No deviations between national survey and Eurostat scope.

The survey is collecting data of internet users, individuals who have used the internet in the three months prior to the survey. Regular internet users are individuals who used the internet, on average, at least once a week in the three months prior to the survey.

This annual survey is used to benchmark ICT-driven developments, both by following developments for core variables over time and by looking in greater depth at other aspects at a specific point in time. While the survey initially concentrated on access and connectivity issues, its scope has subsequently been extended to cover a variety of subjects (for example, the use of e-government and e-commerce) and socio-economic analysis (such as regional diversity, gender specificity, differences in age, education and the employment situation). The scope of the survey with respect to different technologies is also adapted so as to cover new product groups and means of delivering communication technologies to end-users.

For more details on the methodology applicable in each survey year, please consult the Methodological Manual for the respective year on CIRCABC - Methodological Manual - Information society statistics (europa.eu).

Deviations from standard ICT concepts: No deviations from standard ICT concepts.

Households and Individuals

In the ICT usage survey, the target population for the different statistical units is:

- individuals: all individuals aged 16 to 74;

- households: all (private) households with at least one member aged 16 to 74.

Target population composed of households and/or individuals:

• Number of households:  2 275 722
• Number of individuals: 5 158 688

Non-compulsory age groups also included in the target population:

The whole territory of Bulgaria.

Year 2022

Not applicable

Percentages of ‘Households’ and Percentages of ‘Individuals’

Last three months before the interview.

From 11.04.2022 to 17.06.2022.

The legal basis for the 2022 EU survey on the use of ICT in households and by individuals is the Regulation (EU) 2019/1700 of the European Parliament and of the Council of 10 October 2019 establishing a common framework for European statistics relating to persons and households, based on data at individual level collected from samples (OJ  L 261 I, 14.10.2019, p. 1), as implemented by the Commission Implementing Regulation (EU) 2021/1223 of 27 July 2021 specifying the technical items of the data set, establishing the technical formats for transmission of information and specifying the detailed arrangements and content of the quality reports on the organisation of a sample survey in the use of information and communication technologies domain for reference year 2022 pursuant to Regulation (EU) 2019/1700 of the European Parliament and of the Council (OJ L 2269, 27.07.2021, pp. 1-45).

Complementary national legislation constituting the legal basis for the survey on the use of ICT in households and by individuals: No complementary national legislation. The survey is part of the National Statistical Programme for year 2022 adopted by the Council of Ministers.

Not available.

The national Statistics Act (Chapter 6 “Protection of secrecy”) guarantees the protection of statistical confidentiality and the use of individual data collected through statistical surveys for statistical purposes only.

According to art. 25, p. 3 of the Statistics Act "statistical information which aggregates data about less than three statistical units or about a population in which the relative share of the value of a surveyed  parameter of a single unit exceeds 85 per cent of the total value of such parameter for all units in the population".

Release Calendar presenting the outputs of the statistical surveys carried out by NSI is publicly accessible on the NSI website. 

The calendar is available on the NSI website: https://www.nsi.bg/en/content/44/basic-page/release-calendar

The data on the use of ICT in households and by individuals are disseminated according to the Rules for Dissemination of Statistical Products and Services of the NSI with no deviations from the general policy. 

Annual

Press release announcing the publishing of results of the 2022 survey on the use of ICT in households and by individuals is released on 09.12.2022 on the NSI website: https://www.nsi.bg/en/node/19914. 

Publication of the main results of the 2022 survey on the use of ICT in households and by individuals is available on the NSI website: https://www.nsi.bg/sites/default/files/files/pressreleases/ICT_hh2022_en_JMM9789.pdf.

Other publications containing ICT survey data are available on the NSI website, section Information Society, ICT usage in households, Publications.

Selected tables with aggregated data of the survey on the use of ICT in households and by individuals are accessible via:

- NSI website: https://nsi.bg/en/content/2805/ict-usage-households

- Information System INFOSTAT: https://infostat.nsi.bg/infostat/pages/module.jsf?x_2=240&lang=en

Not available.

Individual anonymous microdata could be provided for scientific and research purposes by individual request according to the Rules on Provision of the Anonymised Individual Data for Scientific and Research purposes of the NSI.

Information service could be provided by request, according to the Rules for Dissemination of Statistical Products and Services of the NSI.

Not available.

National reference metadata files are available on the NSI website, section Information Society, ICT usage in households, Metadata and methodology.

Not available

Quality related report of the survey on the use of ICT in households and by individuals is available on the NSI website, section Information Society, ICT usage in households, Quality reports.

There is a quality management system in the NSI in accordance with the requirements of ISO 9001:2015. Since 2019, an extended scope of the system has been approved, including receiving, data collection, processing, storing, analyzing, providing and dissemination of statistical information. Documents related to the quality management in the NSI are available on the NSI website: https://nsi.bg/en/content/471/basic-page/quality.

The quality of the data on the use of ICT in households and by individuals is assured by strictly following the national procedures and the Methodological manual in the field of the information society statistics of Eurostat, which ensures conformity with the standard quality criteria - relevance, accuracy, reliability, timeliness, comparability and coherence. 

The quality management system certified in accordance with ISO 9001:2015 and application of the uniform methodological documents, rules and procedures at all stages of the survey ensure very good quality of the data. Data for all mandatory and optional variables are provided on time to Eurostat in accordance with requirements of the EU Regulation in the field of ICT usage. Standard errors calculated for the requested indicators are within the acceptable levels. The response rate is considered very high - unit response rate 87% (households); item response rate 100%.

Main users of the data are ministries, government agencies, research institutions and other users from the country, as well as the European Commission, ITU and other international organizations.

A general survey on user satisfaction with the offered statistical data products and services is conducted annualy by NSI.

All variables (mandatory and optional) required for transmission have been included in the microdata. 

All variables (100%)

In statistical sampling surveys, the estimation of the parameters obtained from the survey could vary from those in the general population due to sampling errors, errors due to non-response, errors in registration or processing, etc. The minimum effective sample size for the survey on the use of ICT in households in order to compensate for all kinds of non-response is achieved, as defined in the Regulation according to the size of the country and ensuring minimum precision requirement for the key indicator at national level. The precision requirement set out in the Regulation is successfully achieved as well.

The standard error is calculated using the procedure Complex samples analysis of IBM SPSS Statistics by Taylor Linearization Method of Variance Estimation. The procedure estimates variance by taking into account the sample design used to select the sample - including probability proportional to size (PPS) method at the first stage and SRS sampling procedure at the second.

Precision estimates for the question "Individuals having ordered goods or services for private use over the internet in the last 12 months" (individuals who ticked 'Within the last 3 months' or 'Between 3 months and a year ago' in question D1 of the 2022 model questionnaire):

Number of respondents (absolute value for ‘Yes’ answers): 3187

Estimated proportion (in %): 40.5  

Standard error (in percentage points): 0.97

Details of the breakdowns are available in Table 13.2.1. of INFOSOC_HHNSI_A_BG_2022_0000_an1 in the Annexes. 

See more details on non-sampling error below.

Population Census 2011 database updated annually based on current demographic statistics data (deaths and births) is used as sampling frame. There are shortcomings in terms of insufficient update of the population frame, e.g. new buildings (dwellings), demolished buildings, internal and external migration.

Not available.

Not requested in the ICT survey.

1)       Measurement errors: 

These are mainly errors in the interviews stage of data collection, errors due to the respondents’ misunderstanding of questions and inaccurate answers as well as errors taking place at the stage of data codification and recording. The survey on the use of ICT in households is voluntary survey performed by face-to-face interview technique by experienced NSI staff who check the correctness and completeness of the answers by asking additional questions to minimize the occurrence of this type of errors. Proxy interviews are not allowed and up to 3 visits of the households are made in order to collect reliable and good quality data. The data entry program is designed to guarantee correctness and consistency of the initial data (logical controls, acceptable value, etc.).

2)       Questionnaire design and testing: 

The questionnaire design follows the 2022 model questionnaire provided by Eurostat, in order to assure the international comparability of the data. The questions are duly translated and adapted to the national specifics. The questionnaire is tested internally prior to data collection.

3)       Interviewer training: 

Interviewers engaged for the survey are experienced staff of the regional offices of NSI. They are equipped with instructions in paper form, which provide description and explanations for each question, as well as general methodological guidelines for conducting the interview. There is also a glossary of the basic technical terms used in the questionnaire. The interviewers are instructed and assisted by the regional coordinators of the survey prior to and during the fieldwork.

4)       Proxy interview rates: Proxy interviews are not allowed.

Information about non-respondents: Not available.

The unit response rate is the ratio of the number of in-scope respondents (= the number of achieved interviews or the net sample size to the number of eligible elements selected from the sampling frame).

Unit non-response rate for

• Households: 0.13
• Individuals (aged 16-74): 0.22

 Comments, if any: No comments.

1)       Methods used for dealing with unit non-response: 

The unit non-response is treated by correction factor in the weighting procedure.

2)       Methods used for minimizing unit non-response:

Following measures have been taken in order to keep the unit non-response as low as possible:

• press announce about the survey is made at regional level prior to the start of the field work;
• the questionnaire is accompanied with a letter to the household describing the objectives of the survey, the importance for providing information and data security issues; 
• the interviewers are experienced staff of the NSI’s regional offices which raises the trust and confidence of the respondents;
• up to 3 visits to the households are made. 

3)       Substitution permitted: No

4)       Substitution rate (in %): Not applicable

Items with low response rates (observed rates in %): Not applicable.

Data checking and editing is done in three stages:

-  during data collection - interviewers check the correctness of information through asking the respondents additional questions;

-  during data entry - consistency and logical controls are implemented in the data entry software and incorrect data cannot be entered;

-  during data processing - additional checks for logical consistence and year-to-year checks are carried out over the aggregated data.

Not requested for ICT Survey

The data are disseminated at national level on 09.12.2022.

No time lags.

No time lags.

The data are fully comparable at  EU level. At national level, the sample is specially designed to present comparable data between regions of the country.

Not relevant

Possible limitations in the use of data for comparisons over time: Not relevant.

The length of comparable time series depends on the module and variable considered within each of the modules of the survey.

Not applicable

Not applicable

Not applicable

All statistics are coherent within the dataset.

MANDATORY questions in the Eurostat model questionnaire 2022: There are no deviations in the mandatory questions of the questionnaire.

Table 15.4.1. of INFOSOC_HHNSI_A_BG_2022_0000_an1 in the Annexes lists the questions that do not reflect the coverage of subjects and characteristics of Annex 2 of the Commission Delegated Regulation (EU) 2021/1898 of the 20 July 2021. 

Adoption of OPTIONAL questions and items in the Eurostat model questionnaire 2022: There are no deviations in the optional questions of the questionnaire.

Table 15.4.2. of INFOSOC_HHNSI_A_BG_2022_0000_an1 in the Annexes lists the optional questions from the annual Eurostat model questionnaire 2022 included in the national questionnaire and their coverage for age groups beyond the standard scope. 

Additional questions introduced in the national questionnaire: No additional questions have been added to Eurostat questionnaire.

Effects of deviations from the routing used in the Eurostat model questionnaire: All statistics are coherent within the dataset.

In accordance to the Rules for Dissemination of Statistical Products and Services of the NSI.

There are no planned or unplanned revisions of the ICT survey data.

Not relevant

The source of the raw data is described with more details in the paragraphs below.

Тhe frame population is based on the 2011 Population Census database, which is updated annually based on current demographic statistics as of 31 December (deaths and new-borns). The sampling frame consists of all individuals aged between 16 and 74 residing in private households. The survey on the use of ICT in households and by individuals is stand-alone survey and it is carried out on a voluntary basis. 

Sampling units for the survey on the use of ICT are "households" which are selected by a two-stage stratified clustered random sampling. The sample is stratified by NUTS 3 area (28 districts) and by location (town/village). All members of the selected households aged between 16 and 74 years are surveyed. The survey does not have a longitudinal component.

Annual

1) Methods used to gather data: PAPI

2) Short description of the survey method: Face-to-face interview

3) Variables completed from an external source: No variables are completed from an external source.

Data validation is done by logical and consistency checks of the aggregated data and comparison with the results of previous studies. The validation tool provided by Eurostat is in use as well.

Data editing is done in accordance with the validation rules in the Transmission format provided by Eurostat. Imputation methods are not applied. The non-response adjustment is done by weighting factors. Calibration is applied on both households and individuals data. The latest available demographic data for the total population is used for weighting.

For the target indicator "Individuals having ordered goods or services for private use over the internet in the last 12 months" (individuals who ticked 'Within the last 3 months' or 'Between 3 months and a year ago' in question D1 of the 2022 model questionnaire):

Imputation rate (% of observations): 0

Imputation rate (share of estimate): 0

Methods used to impute item non-response: None

Grossing up procedures have been applied to: Households and individuals 

Description of the weighting procedures: 

The first step of the weighting procedure is the calculation of design weights, which represent the inverse of inclusion probabilities of the sample units. According to the country specifics, the sample is stratified to 56 strata by NUTS 3 (28 regions) and location (town/village).

The next step is adjustment of the non-response. The procedure used is “weighting classes”. The classes are defined by the sampling design strata. The reason for this is the limited information available for the non-responding households.

The final step is calibration of the non-response weights to population totals. Calibration is done using the SAS Macro Calmar 2. The main source for calibration totals is the Information System “Demography”. Another source of information is the 2011 Population Census database. As a result, individuals in the net sample are weighted to represent the population as of 31.12.2021 by the groups defined below.

The calibration is applied on both household and individual level:

• Household level:

   - Number of households by NUTS 3 region (28 groups)

• Individual level:

   - 6 age groups (16-24, 25-34, 35-44, 45-54, 55-64, 65-74) by sex (12 groups)

   - Number of persons by NUTS 3 region and location (56 groups)

An integrative calibration design is applied. As a result, all individuals of a specific household receive equal weights and these weights correspond to the calculated household weights.

The calibration method used is “Logit” method (m=3 in Calmar) where the lower bound for g-weights is 0.3 and upper bound is 3.45.

Not relevant

Not relevant

No comments.