1. From the Institute for Firearm Injury Prevention, University of Michigan (P.M.C., R.M.C.), the Department of Emergency Medicine, University of Michigan Medical School (P.M.C., R.M.C.), and the Department of Health Behavior and Health Education (P.M.C., R.M.C.) and the Youth Violence Prevention Center (P.M.C.), University of Michigan School of Public Health — all in Ann Arbor.