1. Tuck School of Business at Dartmouth, 100 Tuck Hall, Hanover, NH 03755, CEPR, and NBER (email: )
2. Imperial College Business School, South Kensington Campus, London, SW7 2AZ, UK, CEP, and CEPR (email: )
3. World Bank, 1818 H Street NW, Washington, DC 20433 (email: )