https://door.donau-uni.ac.at/o:5687 Register data sources on migrant stocks Peitz, Laura Laura Peitz 0000-0003-4495-591X Federal Office for Migration and Refugees text eng Key points • Analysing irregular migrant stocks using register or other administrative data can prove challenging given the usually undocumented nature of the phenomenon; yet, some recent efforts highlight the potential of register data. • The German Central Register of Foreigners (AZR) provides longitudinal data on non- Germans staying or having previously stayed in the country, including subsets of irregularly staying migrants, allowing for in-depth analyses of various research questions. • Throughout, the chapter provides real-life examples of how register data has been used in irregular migration research across different countries. Register data administrative sources migrants under an obligation to leave toleration Irregular migrant stocks Data integration AZR Germany Duldung http://creativecommons.org/licenses/by-nc/4.0/ https://door.donau-uni.ac.at/api/object/o:5687/download 10.48341/g31s-vq79-07 https://door.donau-uni.ac.at/o:5698 application/pdf 83 92 412.78 kB 2025-09-30