1. Department of Social Statistics, University of Manchester, Manchester, Lancashire, UK
2. Department of Statistical Methods, Institut fur Arbeitsmarkt- und Berufsforschung, Nurnberg, Bayern, Germany
3. Department of Sociology, Universitat Mannheim Fakultat fur Sozialwissenschaften, Mannheim, Germany
4. Data and Research on Society, GESIS – Leibniz Institute for the Social Sciences, Mannheim, Baden-Württemberg, Germany