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Study: MZ 2011

Additional Programs

  • Additional Programs
    • Health insurance (Sampling Fraction: 1% )
    • Additional information on economic activity (II) (Sampling Fraction: 1% )
  • Ad-hoc-module EU Labour Force Survey
    • Employment of disabled people (Sampling Fraction: 0.1% )

Specific Features

Changes In Questionnaire

  • To improve the measurement of ILO labour status, in particular, the fieldwork and questions relating to labour market participation have undergone changes since the 2005 round of the Microcensus. In the 2011 round, some of the Microcensus (MC) and Labour Force Survey (LFS) questions underwent changes compared to the previous year. This was implemented within the framework of a methods project using a split ballot technique: the new questionnaire was administered to a 0.9% subsample, while a questionnaire corresponding largely to the original concept was administered to a 0.1% subsample.
  • A new question that introduces the employment-situation section is of central importance. This question, which relates to the so-called “main status” (F18; EF66), measures the respondent’s current social status. (However, variable EF66 is not part of the scientific use file [SUF].1) The relevant information on the existence of a paid job, which is required to implement the ILO labour force concept, is not collected until after this question has been asked.
  • This new approach gave rise to further changes in the questionnaire. Several of the questions that are still featured in the questionnaire administered to the 0.1% subsample became superfluous in the new questionnaire administered to the 0.9% sample (e.g. F20a; EF81). On the other hand, some new questions had to be added (e.g. F19; EF67) or existing questions relocated (F22/F18a; EF77). Moreover, some questions were partly reformulated (e.g.. F23/F22a; EF85) or simplified (e.g. F22/F18a; EF77).
  • In all, the changes improved the measurement of employment and unemployment and reduced the divergence between the survey data and the reference statistics. The new concept will therefore be retained in 2012 and beyond. For methodological reasons, the results for 2011 are comparable only to a limited extent with those of previous years. Moreover, it should be noted that the answers to these different versions of the questionnaire were incorporated into the uniform classifications by type, for example EF29: Labour status type and EF38: Unemployment type (see the comparison of the questionnaire versions [in German] and the methodological information in the data handbook (both of which are available in German only). In the system files, the respective variables are identified by indicating in the variable label the question numbers (F…/…) and the sampling fraction of the subsample (0.9 % / 0.1 %).
  • In 2011, the response categories for the “school or higher education institution attended” (EF289) and the “highest completed level of vocational education and training” (EF312 etc.) were expanded, with the result that direct comparison with previous rounds is possible only to a limited extent.
  • A conceptual change was made to questions about migration and integration. Up to 2010, respondents who had left the Federal Republic of Germany for more than six months after they first moved here, were asked to report the year of their last move to the country. In 2011, by contrast, respondents were asked to state the year of their first move to Germany (EF367), even if their period of residence in the country had been interrupted since then. In addition, the year of their return to Germany after the last interruption is measured with a new question (F129; EF384). This has an effect on the classifications of migrant status by type, which are derived from these variables.
  • The notes on the questions relating to health insurance, which are available only in German, provide further information on the measurement of health insurance and its comparability with 2007.
  • In 2011, the ad hoc module “Employment of disabled people,” was implemented within the framework of the EU Labour Force Survey using a sampling fraction of 0.1%. The variables in question are EF1084-EF1096.
  • A module on this topic was last implemented in 2002 (see variables EF420-EF425 in the 2002 SUF). It is important to note that the variables EF1090u1-EF1096 also include hypothetical questions. While questions 161-167 relating to health status and employment are addressed to persons aged between 15 and 64 years – that is, persons with a paid job or contributing family workers who have answered “yes” to at least one of the main questions for the measurement of ILO labour status (F18a-F21a; EF77-EF79, EF81) – questions 168-174 on health status and possible employment are directed to persons who are not employed – that is, other persons who do not have a paid job. For example, the variables EF1090u1-EF1090u5 contain both (multiple-) responses from employed persons to question 161: “Is the number of hours that you work in a week limited?”, and (multiple) responses from persons who are not employed to question 168: “Would the number of hours that you worked in a week be limited if you were working?”

Methodical Notes

  • When constructing the extrapolation factor EF956 used for the variables of the 2011 ad hoc module, the survey method (EF7), the labour status type (EF29) differentiated according to sex (EF46) and age group (EF44) at federation (Bund) level, the labour status type (EF29) differentiated according to sex (EF46) at federal state (Land) level (EF1), and the two nationality groups German/foreign nationals in the regions East/West were deployed to estimate the response probabilities (1st stage). The target population comprises persons aged between 15 and 64 years. When carrying out the adjustment (second stage), values for the variables “labour force type”, “sex”, and “age groups” were adjusted at the regional levels “federation” and “federal states” (Bundesländer) to extrapolated sample values of the Microcensus. For East Germany (without Berlin) and West Germany (incl. Berlin) they were also adjusted to population values by groups of nationalities.

New Classifications

  • Since 2011, the 2008 version of the International Standard Classification of Occupations, ISCO-08, has been used in the EU Labour Force Survey (EU-LFS). Accordingly, this revised version was deployed in the 2011 Microcensus (see EF517, EF521, EF739, EF827, EF851). The occupations according to ISCO-08 were coded into the 1992 Klassifikation der Berufe using a conversion key. The ISCO-88 COM was no longer implemented in the original file. For the SUF, however, ISCO-88 COM was generated once again. This applies also to the derived variables for the main income earner (EF739a), the reference person of the living arrangement (EF827a) and the cohabiting partner of the living arrangement (EF851a).

Year Specific Documentation

  • Estimation of Income for the Variables EF707 and EF806 [in German] [.pdf]
  • Annotations about the Topic Health Insurance [in German] [.pdf]
  • Microcensus Scientific Use File 2011 Documentation and Data Preparation [in German] [.pdf]

Target Sample Size

Cross-sectional Data
Sampling Units Districts
Achieved Sample Size 486100


Units Of Observation

  • Persons (in private households and collective dwellings)
  • Households

Units Of Analysis

  • Persons
  • Living arrangements
  • Families
  • Households

Data Collection

Start Date


End Date


Participation Mandatory


Interview Mode

  • 70.6 % CAPI
  • 8.4 % CATI
  • 21 % Self-administered

Percentage Of Proxy Interviews

23.67 %


Design Weight: Target

Dwelling, Household, Persons

Design Weight: Method

The Microcensus is a single-stage, stratified cluster sample with a uniform sampling fraction for all strata. As a rule, the sampling fraction is 1 %; it applies to all sampling units (sampling districts, dwellings, households, persons).

Because the selection probability of the Scientific Use File (SUF) basically remains constant at 70%, design weights can be created on the basis of the inverse of the sampling fraction of the Microcensus (1 %) and the Scientific Use File (70 %): w = 1 / (0.01 * 0.7).

Non-response Weight: Method

In the Microcensus, as in all surveys, the sampling plan cannot be realised fully. Hence, undercoverage occurs in the form of non-response on the part of the households to be surveyed. Because households and their members are obliged by law to provide information for the Microcensus, non-response is due mainly to the fact that households could not be reached during the survey. Cases of non-response are corrected using the information that is available about the non-responding households.

Since 2005, the compensation factors are no longer calculated by dividing target figures by actual figures but rather by means of generalised regression estimation (calibration technique). At regional level, the following characteristics, or combinations of characteristics, are taken into account for private households: rotation quarter and new-construction stratum (federal state), 19 compensation classes (see above; regional adjustment stratum), and total private households (regional subgroup). For collective dwellings: number of persons in collective dwellings (regional subgroup).

Coverage Adjustment Weight: Method

In contrast to compensation, adjustment is carried out at person level.

Since 2005, adjustment has no longer been carried out at the level of disjointed adjustment strata but rather on a quarterly basis at different regional levels; data from the Central Register of Foreign Nationals (Ausländerzentralregister) are also used. Moreover, the same extrapolation factors are available for all members of a household. The extrapolation terms and regional units are: age groups x sex; nationality groups x sex; population group (temporary career volunteers and regular soldiers including members of the Federal Police and the Bereitschaftspolizei (riot police), persons doing military service, civilian population) (federal state); nationality groups x sex (administrative district); total population (regional adjustment stratum).

Final Weighting: Method

For the final weight a two-stage procedure is employed: In a first step the net sample of the successfully interviewed households is adjusted to the gross sample of all households to be interviewed (compensation). In a second step this gross sample is benchmarked to the update of the current population figures (adjustment). The final weights result from a combination of this two-stage procedure of compensation and adjustment. They are derived from the original data, are already multiplied with the inverse of the selection probability and extrapolated to 1000 of the population.

From 2005 onwards, in addition to the standard weighting factors for annual averages there are also weighting factors for the quarterly samples, for the ad hoc modules and structural variables of the EU-LFS. Moreover, there are special weighting factors for supplementary programmes of the Microcensus (e.g., on the housing situation).

See [.pdf] (in German)