Migration to Germany - how reliable are the statistics?

Great attention has been given to migration to Germany and the integration of migrants into German society, and statistical information on migration and on migrants living in Germany is urgently needed since, in order to develop a successful migration policy, empirically grounded knowledge is necessary. Only if the data basis is sufficiently reliable can policy proposals be formulated. In this point all the experts agree. But how well-founded and internationally comparable is the information that the statistics provides? Thomas Straubhaar, Hamburg Institute of International Economics (HWWI), underlines, first of all, that at the international level tremendous differences sill exist: "In spite of many efforts that have resulted in respectable improvements, migration data are only conditionally consistent internationally and comparable only to a limited extent. Between the migration statistics of the International Bank for Reconstruction and Development, Eurostat or OECD, there are huge gaps." Also for Barbara Dietz of the Munich Eastern Europe Institute, migration in Germany raises the question of whether cross-border movements are adequately registered, whether the data are internationally comparable and whether the results of migration, can be reliably estimated. Johann Hahlen, Federal Statistical Office, points out in his contribution that even if the statistic gathering is carried out reliably, some unclarity is inevitable since the underlying data sources are primarily used for administrative and not statistical purposes. Improvements of the data quality are meant to be achieved particularly by the new micro census of 2011 but also by the full implementation of the data exchange obligation between the general registration offices and the alien registration authorities.