RAND Corporation, Santa Monica, CA, USA. Electronic address: jluoto@rand.org. RAND Corporation, Santa Monica, CA, USA. Department of Psychology, McGill University, Montreal, QC, Canada. Department of Psychiatry, Sinai Health and University of Toronto, Toronto, ON, Canada. Division of Community Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, CA, USA. Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA. Safe Water and AIDS Project, Kisumu, Kenya.