1. Martin Huber is Professor of Applied Econometrics at the Department of Economics, University of Fribourg. Michael Lechner is Professor of Econometrics at the University of St. Gallen, Swiss Institute for Empirical Economic Research. He is affiliated with CESIfo, Munich, and IZA, Bonn, as well as with CEPR PSI, London, and IAB, Nuremberg. Conny Wunsch is Professor of Labor Economics at the Department of Labour Economics, University of Basel.