Since 1957 the Microcensus is conducted with a sampling fraction of 1% of the persons and households in Germany. It supplies basic socio-demographic data and facilitates the ongoing monitoring of the labour market. The European Union Labour Force Survey (EU-LFS) is integrated into the Microcensus.
The survey programme of the Microcensus consists of a core programme with focus areas on households, family and labour market that remains the same in each round. In addition to the variables in the core programme, further information on topics such as migration, childbirths, labour market participation, and housing conditions is collected within the framework of supplementary programmes with varying sampling fractions.
In 2005 the mode of data collection was changed, and data was no longer collected during a fixed timeframe but for the entire year. The Microcensus uses a single-stage stratified cluster sampling method with a sampling fraction of 1%. The sampling districts (primary sampling units) consist of clusters comprising, as a rule, neighbouring buildings. The households of each sampling district remain in the sample for four years. Each year, a quarter of the sampling districts are replaced by newly introduced sampling districts. Households and persons who move away from the sampling district are not followed but rather replaced by households and persons moving into the sampling district. Therefore the Microcensus is a repeated rotating panel survey, with partial overlap of sampling units.
In general, the survey data are collected via computer assisted personal interviewing (CAPI). Besides from that some respondents complete a self-administered questionnaire or a computer assisted telephone interview (CATI). However, the proportion of proxy-reports is about 25% (based on persons who are at least 15 years old). Furthermore, sampled households and their members are obliged by law to provide information for the Microcensus. Some questions and topics are exempt from this law.
The Microcensus provides an enormous sample size, a very high utilisation of the sample, and its characteristics as a multi-topic as well as a replicative survey. Therefore the Microcensus is an important data source for the investigation of many research questions in the empirical social sciences. The Scientific Use File (SUF) as a de-facto anonymised 70% subsample of the households in the Microcensus is available for researchers.