Ilka Steiner is a scientific collaborator at the Institute for Demography and Socioeconomics of the University of Geneva and part of the nccr – on the move. Also, she is a lecturer in Demography at the University of Neuchâtel in Switzerland. She is currently based the Stockholm University Demography Unit (SUDA) as a guest researcher. Her research interests lie in immigrant demography. She obtained a PhD in Demography from the University of Geneva with a focus on remigration intentions and behaviour of immigrants, under the provision of free movement of persons. In this framework, she launched a new register based longitudinal data base for migration research in Switzerland that is today used by several research teams of the nccr – on the move. Also, she coordinated the implementation of two national surveys among immigrants living in Switzerland, thereof the first wave of the Migration-Mobility Survey. Currently, she is involved in a subproject on the impact of family formation on return migration from a comparative perspective, between Switzerland and Sweden.Philippe Wanner is professor of demography and head of the Institute of Demography and Socioeconomics at the University of Geneva. He holds a Bachelor in Economics and a PhD in Demography. He is also Deputy Director of the nccr – on the move. His research focuses on the demographic impacts of migration and on the processes of integration, as well as on the measure of migratory flows and integration dynamics. He recently edited a book on the demography of migrants (2012) and a book on the demographic trends in Switzerland (2014). He is also author and co-author of different peer-reviewed papers on migration and integration, including the integration on the labour market or migrants' health.