Bastian Hartmann Chair in Social Policy and Institutional Economics, Ruhr-University Bochum   Ruhr-University Bochum Faculty of social science Universitätsstraße 150 Bochum, 44801 Germany   bastian.hartmann@ruhr-uni-bochum.de   www.rub.de/sozialpolitik           JEL Areas: D : Microeconomics J : Labor and Demographic Economics