Estimation methods and survey approaches for research on irregular migration

Migration Department

Project head: Dr. Franck Düvell

Quantitative research on the situation of undocumented migrants is a particular challenge for the social sciences due to methodological problems and a lack of data. Some official data sets do allow conclusions to be drawn about individual forms of irregular residence in aggregated form. Some qualitative studies have also succeeded in interviewing irregular migrants to a limited extent. However, there is a lack of corresponding macro and micro data. There is a great need for valid and broader data sets, for example, to determine the magnitude of this social problem and to be able to discuss possible solutions. This project explored the question of which quantitative methods are suitable for estimating the extent of irregular migration in Germany.

Results: First, data on irregular migrants were collected from available sources (Central Register of Foreigners, BAMF, DESTATIS, answers of the Federal Government to small questions in the German Bundestag, Federal Police, IOM Germany) or generated by special analyses. The analysis showed that the number of registered irregular migrants (bright field) is low. The dark field can only be estimated. A recent estimate by the US research institute PEW was critically reviewed and found to be based on crucial assumptions and therefore unusable. This was presented in a research note. In addition, two international workshops on the topic were held, the BMFSFJ, the BAMF, the European Commission and the Diakonie Hessen were supported with advice, and the results were presented at the 16th annual conference on "Illegality" of the Catholic Academy in Berlin. In addition, further publications are in the works.

Funding: Federal Ministry of Family Affairs, Senior Citizens, Women and Youth (Institutional funding)