1. Departments of Psychiatry and Behavioral Health (Prater, Zatzick), Pediatrics (Ellyson, Rivara), and Epidemiology (Shawon, Cheung, Rowhani-Rahbar), University of Washington, Seattle; Firearm Injury and Policy Research Program, Harborview Injury Prevention and Research Center, Harborview Medical Center, University of Washington, Seattle (Prater, Ellyson, Rivara); Social Development Research Group, School of Social Work, University of Washington, Seattle (Lyons).