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Study: MZ 2008

Additional Programs

  • Additional Programs
    • Biological number of children for all women aged 15 to 75 years (Sampling Fraction: 1% )
    • Commuting characteristics of employed persons, pupils and students (Sampling Fraction: 1% )
  • Ad-hoc-module EU Labour Force Survey
    • Migration and Job Market (Sampling Fraction: 0.1% )

Specific Features

Changes In Questionnaire

  • In order to improve the documentation of ILO labour-force status, not only have several of the questions pertaining to job-market participation been modified since 2005, but the field work has changed as well. In the 2008 collection of data, some questions are worded differently or contain different categories of answers as compared to 2007 (compare table 1 in: Boehle, Mara und Bernhard Schimpl-Neimanns, 2010: Mikrozensus Scientific Use File 2008: Dokumentation und Datenaufbereitung. GESIS-Technical Reports Nr. 2010/13. Mannheim: GESIS - Leibniz-Institut für Sozialwissenschaften). Distributional differences can thus be due to changes in the job market or, alternatively, may be due to the modification in the method (new questions) (see Köhne-Finster and Lingnau 2008; Körner and Puch 2009); see especially EF62-EF88, EF138, EF140, EF147.
  • The questions regarding school attendance (EF287-EF293) have been modified. In 2008, the three questions formerly asked about the type of general-education school, vocational school and university/university of applied science attended (MC 2007, questions 88a-88c, variables EF289-EF291) were combined into a single question (question 92, EF289).

Methodical Notes

  • As in 2006 (but not 2007), the 2008 Microcensus contains so-called “Jahresüberhänge” (households or individuals who, generally due to difficulties in contacting them, could not be questioned during the period the census was being conducted [2007] and were instead surveyed the following year [2008]); see EF5b (compare Boehle, Mara und Bernhard Schimpl-Neimanns, 2010: Mikrozensus Scientific Use File 2008: Dokumentation und Datenaufbereitung. GESIS-Technical Reports Nr. 2010/13. Mannheim: GESIS - Leibniz-Institut für Sozialwissenschaften).
  • When drawing random sub-samples for the Scientific Use File (SUF) from the original data, "Jahresüberhänge" were taken into consideration and reflected in the household numbers; i.e. the household number is made up of the code for the "Jahresüberhang" (EF5b) plus the original household number. When there are "Jahresüberhänge", in the SUF the household number for the selected region (EF4) is identical to the household number used in the annual figures from 2008. This is why – for some particular definitions at the level of household, family or other forms of life – the following sorting order must be used to assure a clear identification of the units: selected district (EF3), reporting annual quarter (EF12), "Jahresüberhang" (EF5b) and household number (EF4) plus, if required, the number of the form of life in the household (EF27) or the number of the family in the household (EF25).
  • For sub-samples drawn for the Scientific Use Files, the sub-sample ID code has been included as an additional sorting feature and placed in third position, after the codes for the quarter and the federal state. This contributes to improving the quality of the results for the sub-sample (ad hoc module, AKE [EU Labour Force Survey] structure variables).
  • For the ad hoc module “Migration and Labour Market” and the structural variables of the EU Labour Force Surveys carried out within the framework of the 0.1% random sub-sampling (see EF6) and with no duty of disclosure (EF118, EF177-EF179, compare table 1 in: Boehle, Mara und Bernhard Schimpl-Neimanns, 2010: Mikrozensus Scientific Use File 2008: Dokumentation und Datenaufbereitung. GESIS-Technical Reports Nr. 2010/13. Mannheim: GESIS - Leibniz-Institut für Sozialwissenschaften), projections from 2008 (EF956 or EF955) are available.

New Classifications

  • NACE Rev. 2, the new classification system for the economic sector in the EU, has as a rule been used in the EU Labour Force Survey since 2008. The corresponding updated version for the classification of economic branches (2008 edition), however, has only been applied in the German Microcensus since 2009. With the help of a double coding system based on the classification systems of 2003 and 2008, over the course of the 2009 Microcensus (January – April) and other assessments, a crosswalk was created so that data for 2008 could be conformed to the new classification system and retroactively made available. The Scientific Use File contains these variables.

Changes In Typification

  • Only non-working people are now included in variable EF38 categories of non-employment, whereas up until 2008 both employed and unemployed people had also been included.


  • Issues of data protection made it necessary to simplify the categories of variables dealing with community size (EF 563) in Mecklenburg-Western Pomerania und Saxony. For further information about these and other points, please see the commentaries relating to the variables in question in the 2008 Microcensus Data Handbook.

Year Specific Documentation

  • Imputation Procedures on Information about Birth (Paper of the Federal Statistical Office) [in German] [.pdf]
  • Classification of EF38 Non-working Population (new from 2008 onwards) [in German] [.pdf]
  • The Concept of Migration Background in the Microcensus SUF 2008 [in German] [.pdf]
  • Estimation of the Classification of the Economic Sector WZ 2008 for the MZ 2008 (Papier of the Federal Statistical Office) [in German] [.pdf]
  • Microcensus Scientific Use File 2009 Documentation and Data Preparation [in German] [.pdf]

Target Sample Size

Cross-sectional Data
Sampling Units Districts
Achieved Sample Size 484422


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

  • 76.9 % CAPI
  • 3.3 % CATI
  • 19.8 % Self-administered

Percentage Of Proxy Interviews

25.95 %


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 (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 also exist 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)