1. Department of Public Finance, University of Innsbruck, Universitaetsstrasse 15, A–6020 Innsbruck, Austria.
2. Department of Management, London School of Economics, Houghton Street, London WC2A 2AE, United Kingdom, and University of Cologne, Albertus-Magnus-Platz, D–50923 Cologne and IZA Bonn, Schaumburg Lippe Strasse 5–9, D–53113 Bonn, Germany.
3. Department of Public Finance, University of Innsbruck, Universitaetsstrasse 15, A–6020 Innsbruck, Austria, and Department of Economics, University of Gothenburg, Vasagatan 1, 40530 Gothenburg, Sweden, and IZA Bonn, Schaumburg Lippe Strasse 5–9, D–53113 Bonn, Germany.