Ioana Salagean holds a PhD in economics from the University of Nancy 2 in France and worked as Assistant Professor for M.Sc. IMPALLA. She currently works for Luxembourg Income Study (LIS) and the National Statistical Institute of Luxembourg (Statec) analyzing empirically poverty and living conditions in a national as well as a comparative perspective. Catalina Lomos obtained a PhD degree in Education from University of Groningen in the Netherlands, and she worked between 2011 and 2015 as an assistant professor in the International MSc in Social Policy Analysis (IMPALLA) and as a post-doctoral researcher at the Luxembourg Institute of Socio-Economic Research (LISER, formerly CEPS/INSTEAD), G.D. Luxembourg. Since 2015 she continues her work as a researcher at LISER, her empirical focus being on student achievement within the framework of school effectiveness research, and on cross-cultural comparisons implying measurement invariance. In addition, since 2012, Catalina has been closely collaborating with the Ministry of Education, Children and Youth in Luxembourg, in different national projects. Anne Hartung is research associate at the IRSEI Institute for Research on Socio-Economic Inequalities, University of Luxembourg investigating stratification and inequalities and previously worked as Assistant Professor for the M.Sc. IMPALLA at the University of Leuven, Belgium and LISER, Luxembourg.