1 Maastricht Graduate School of Governance, United Nations University-MERIT (UNU-MERIT), Maastricht University , Maastricht , Netherlands ; Department of Economics, University of Liege , Liege , Belgium.
2 Top Institute Evidence Based Education Research (TIER), Maastricht University , Maastricht , Netherlands ; Department of Health Services Research, Faculty of Health, Medicine and Life Sciences, Maastricht University , Maastricht , Netherlands.
3 Department of Health Services Research, Faculty of Health, Medicine and Life Sciences, Maastricht University , Maastricht , Netherlands.
4 Top Institute Evidence Based Education Research (TIER), Maastricht University , Maastricht , Netherlands ; Amsterdam School of Economics, University of Amsterdam , Amsterdam , Netherlands.