1. University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada;
2. Tulane University, A.B. Freeman School of Business, New Orleans, Louisiana 70118;
3. Stern School of Business, New York University, New York, New York 10012;
4. National Bureau of Economic Research, Cambridge, Massachusetts 02138;
5. PBC School of Finance, Tsinghua University, Beijing 100083, China;
6. IZA Institute of Labor Economics, 53113 Bonn, Germany;
7. Center for Economic Studies and Ifo Institute for Economic Research, 81679 Munich, Germany;
8. School of Industrial and Labor Relations, Cornell University, Ithaca, New York 14853