Deven T. Hamilton is with the Center for Studies in Demography and Ecology and Steven M. Goodreau is with the Department of Anthropology, University of Washington, Seattle. Samuel M. Jenness and Patrick S. Sullivan are with the Department of Epidemiology, Emory University, Atlanta, GA. Li Yan Wang, Richard L. Dunville, and Lisa C. Barrios are with the Division of Adolescent and School Health, Centers for Disease Control and Prevention, Atlanta, GA. Eli S. Rosenberg is with the Department of Epidemiology...