1. From the RAND Corporation (R.L.H., L.J.F.) and the Department of Pediatrics, Boston University School of Medicine (L.J.F.) — both in Boston; and the Department of Health Management and Policy, University of Michigan School of Public Health (R.L.H, K.Z.), the Departments of Psychiatry and Obstetrics and Gynecology, University of Michigan Medical School (K.Z.), and the Department of Veterans Affairs (K.Z.) — all in Ann Arbor.