1. Agricultural and Applied Economics, University of Wisconsin, Madison, 427 Lorch St., Taylor Hall, Madison, WI 53706 (e-mail: )
2. Department of Economics, AC #2201, Amherst College, Amherst, MA, 01002 (e-mail: )
3. Office of Strategic Planning and Development Effectiveness, Inter-American Development Bank, 1300 New York Avenue, Washington, DC, 20577 (e-mail: )