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Income and living conditions (ilc)

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National Reference Metadata in Single Integrated Metadata Structure (SIMS)

Compiling agency: Statistics Denmark

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The European Union Statistics on Income and Living Conditions (EU-SILC) is a survey-based instrument aiming at collecting timely and comparable cross-sectional and longitudinal multidimensional microdata on income, poverty, social exclusion and living conditions. In addition, it collects module variables every three years, six years or ad-hoc new policy needs modules.

The EU-SILC instrument provides two types of data:

  1. Cross-sectional data pertaining to a given time or a certain time period with variables on income, poverty, social exclusion and other living conditions;
  2. Longitudinal data pertaining to individual-level changes over time, observed periodically over four‐or more year rotation scheme (Annex III (2) of 2019/1700). Social exclusion and housing condition information is collected mainly at household level while labour, education and health information is obtained for persons aged 16 and over. The core of the instrument is income information at very detailed component level and mainly collected at personal level.

31 May 2025

Statistical concepts and definitions for EU-SILC are specified in Regulation (EU) 2019/1700, Commission Implementing Regulation (EU) 2019/2181, and Commission Implementing Regulation (EU) 2019/2242. Additional information is available in the EU statistics on income and living conditions (EU-SILC) methodology and in the methodological guidelines and description of EU-SILC target variables (see CIRCABC).

Further details are provided in items 5, 15.1.1.1, 15.2.2 and 18.3.

 

The source or procedure used for the collection of income variables

The Danish data on incomes are mainly collected in gross form from registers, stemming from the Danish Tax Authoritie. The only exception is intra-household transfers, that are collected via survey.

Many variables are therefore partly based on Danish tax regulation by design. For this reason, a number of adjustments are made to the variables in order to align the data to the SILC definition of incomes. This is possible for most variables, see a more thorough description on the publication 'revision of SILC incomes'.

The tax paid is subtracted from the gross household income to produce the net household income. Because the Danish tax system is complex and almost all income and deductions are part of a integrated tax calculation, it is not possible to calculate person tax rates for all net income components. The total household income is then distributed among the net components the following way. All income components that are exempt from tax are subtracted from the gross  income. Tax on pensions from indicidual private plans are taxed separately, this tax is removed from both the gross income and the tax paid, to be added later. The adjusted tax paid and gross income are then used to calculate an effective tax rate at the person level. The tax rate is fixed between 0 and 100 percent of the gross income, any tax outside of this range is attributed to income components according to where the largest gross incomes are found. Typically negative tax rates and tax rates above 100 are found for self-employed persons, so most of this excess tax is placed in PY050N.

Comparability and deviation from definition for each income component

All income components are fully comparable

Household definition and membership

Reference population - Persons living in private households on Danish territory at the end of the income reference period
Private household - A person living alone or a group of persons who live together, providing oneself or themselves with the essentials of living
Household membership - A person residing in the household or being temporarily away from the household and sharing the cost of living to a large degree

Description of reference period used for incomes

Period for taxes on income and social insurance contributions: 01 January 2023 - 31 December 2023
Income reference periods used: 2023
Reference period for taxes on wealth: 31 December 2023
Lag between the income ref period and current variables: 2-5 months, depending on the date of the interview. Register data for March are typically used for current register variables

Statistical units are private households and all persons living in these households who have usual residence in the Member State. Annex II of the Commission implementing regulation (EU) 2019/2242 defines specific statistical units per variable and specifies the, content of the quality reports on the organization of a sample survey in the income and living conditions domain pursuant to Regulation (EU) 2019/1700 of the European Parliament and of the Council.

There are two types of general statistical units in the SILC survey. 

Persons - A person living in a private household at the end of the income reference period or a current household member of the sampled person

Households - The entire household of the sampled person

Specific statistical units per variable are defined in Annex II of the Commission implementing regulation (EU) 2019/2242 specifying content of the quality reports on the organization of a sample survey in the income and living conditions domain pursuant to Regulation (EU) 2019/1700 of the European Parliament and of the Council.

The target population is private households and all persons composing these households having their usual residence in the Member State. Private household means a person living alone or a group of persons who live together, providing oneself or themselves with the essentials of living.

Denmark

Description of reference period used for incomes

Period for taxes on income and social insurance contributions

Income reference periods used

Reference period for taxes on wealth

Lag between the income ref period and current variables

 2023

 2023

 2023

 3-5 months lag depending on interview date

According to Reg. (EU) 2019/1700 Annex II, precision requirements for all data sets are expressed in standard errors and are defined as continuous functions of the actual estimates and of the size of the statistical population in a country or in a NUTS 2 region. For the income and living conditions domain, the estimated standard errors of the following indicators are examined according to certain parameters set:

  • · Ratio at‐risk‐of‐poverty or social exclusion to population;
  • · Ratio of at‐persistent‐risk‐of‐poverty over four years to population;
  • · Ratio at‐risk‐of‐poverty or social exclusion to population in each NUTS 2 region.

Further information is provided in section 13.2 Sampling error.

Possible sources of bias

  • Population definition - Some bias may arise when we remove households with 10 adults or more. 
  • Contact at household - Some households cannot be located. If those households differ from the households that can be contacted, a bias will arise
  • Non-response bias - The persons who refuse to participate in the survey are not representative of the sample as a whole. Typically, younger individuals and individuals with lower incomes are more inclined to refuse to participate in the SILC survey.

These problems are partly mitigated through the calibration of weights (see section 18.5). The calibration ensures that AROP60 almost exactly matches the register, so variables that are closely related to the AROP60 have a lower selection bias than variables that are not that related to AROP60.

Steps are continuously taken in order to reduce the non-response rate, which is the largest source of bias effecting the results.

The data involves several units of measure depending upon the variables. Income variables are transmitted to Eurostat in national currency. For more information, see methodological guidelines and description of EU-SILC target variables available on CIRCABC

Data compilation is carried out in several steps, as described below. The first steps of the process only pertain to cross-sectional data. Later, data from previous years are added and longitudinal weights are calculated.

Raw data manipulation and sample update

Data are received from our data collection partner via a secure FTP-server. Data is then transformed to be more compatible with SILC data formats and duplicates are removed. The sample is updated with metadata on the interview and all persons are assigned personal id's (PB030/RB030). The consolidated sample is then used to create the D, H, R and P populations.

Survey and register variables

The data from the survey is then extracted and recoded to comply with modalities in EU-SILC regulation. Seperate programs extract data from registers and edit to comply as well. 

Collection of data, weighting and flag coding

When all variables are produced, they are collected into the D, H, R and P files. Flags are then coded according to regulation and added to the respective files. Weights are then calculated on both a personal and household level.

Longitudinal data

When the cross-sectional data is produced, the data from tre previous three years are gathered from last years transmission. This collected data is used to produce longitudinal weights and ultimately the final EU-SILC dataset.

Data on household composition, current labour market participation and subjective questions are based on interviews. Objective data on housing, education, basic demographics and incomes are based on administrative registers where available.

Survey data

The variables that either cannot or may not be collected from registers are collected via a survey. The survey is designed to meet the definitions laid out in the regulation governing each survey year, customized to fit a national context. The data collection is carried out in spring, by telephone and web. 

Register data

A large part of the SILC survey relies on register data. In general, if a register exists that corresponds with a EU-SILC variable, the register is used instead of adding said variable to the survey. The majority of variables related to income, wealth, population and the dwelling are covered by register. These are the main registers used in the compilation of the SILC variables.

  • Population register (CPR) - Centrally administered population register containing information on the Danish population, with information on sex, age, id's of fathers, mothers and possible spouses, home addresses etc.
  • Income register - Register of incomes from the Danish tax authority covering all persons paying tax in Denmark
  • Wealth register - Register of wealth, collected from numerous sources. Covers most financial and non-financial assets and liabilities of Danish individuals and households
  • Education register - Data from administrative records of the edicational level and activities of the population
  • Building register - A register of residential and non-residential buildings in Denmark, containing details on the use of the building and the building itself
  • e-Income register - A register of incomes sourced from the Danish tax authority. Also contains hours worked and taxable benefits
  • Various government benefit registers - Numerous smaller registers containing information on social benefits have been used in the compilation

Some information from other registers have been used, but to a lesser degree.

Annual

The micro data were submitted to Eurostat by the end of the survey year and less than 12 months after the end of the income reference period.

Data is generally comparable within Europe. But caution is advised, when interpreting minor differences on indicators between countries due to statististical errors and the difficulties related to cross-border income comparisons.

Denmark has participated in the EU-SILC since 2003.

In 2021, the SILC survey was aligned to the EU Regulation 2019/1700 (IESS Regulation - find more information legal framework).  This has introduced some new variables and resulted in changes to some other variables. If there is a breaking change, the variable has received a new name. Therefore there are no known data breaks due to the IESS Regulation.

In 2020, there was a major revision in the method behind the calculation of income variables. Read the detailed description revision of SILC incomes.

In 2018, there was a error in the first days of the data collection. This resulted in 405 rejected households due to a looping issue that caused some household members not to be interviewed.  276 of these households was included in SILC. The labour markets status of the missing houshold members was imuted via income data from the preliminary income register and answers provided in previous years. The issue has been described in more detail in an annex to the quality report.

In 2017, parental leave payments was moved from PY120 to HY050

In 2013, a policy change on private lump-sum pensions, has lead to an increase in private pension pay-outs. The effect is temporary only. As SILC 2014 contains incomes from 2013, the SILC-2014 is the first year affected by this policy-change.
The expected effect on gini is 

  • SILC-2013: +0
  • SILC-2014: +0.31
  • SILC-2015: +0.25
  • SILC-2016 and forth: ~-0.1 (Provided that we are unable to impute the lump-sum pensions).

Threshold indicators such as Risk of Poverty should be virtually unaffected as most people with private lump-sum pensions have incomes above the median.

In 2014 and again in 2016, Statistics Denmark revised the calibration of SILC. The new calibration has been implemented going back to 2011.

From 2011, the income mass within income groups has been included in the calibration to fit the register better. This has been done in order to obtain better consistency between our register data and the EU-SILC data and has significantly lowered the deviations between full register data and the silc data, when measuring average income and the gini-coefficient. Furthermore between 2009 and 2010 the household definition in the callibration changed from adresses to a narrow concept of the family.

For consistent data on the gini-coefficient and similar pure economic indicators pre-2010, it's recommended to use statistics based on Danish register data for the entire population.

Annexes:
Annex 8