1. Markets, Trade, and Institutions Division, International Food Policy Research Institute, 2033 K St. NW, Washington, DC 20006 (e-mail: )
2. Facultad de Ciencias Económicas, Universidad Francisco Marroquin, 6 Calle final, zona 10 Guatemala, Guatemala 01010 (e-mail: )
3. Department of Economics and Gerald R. Ford School of Public Policy, University of Michigan, 735 S. State Street, Ann Arbor, MI 48109, National Bureau of Economic Research (NBER), and the Bureau for Research and Economic Analysis of Development (BREAD) (e-mail: )