1. Andrew Conner, Deborah Azrael, Catherine Barber, and Matthew Miller are with Harvard Injury Control Research Center, Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA. Matthew Miller is also with Bouvé College of Health Sciences, Northeastern University, Boston. Vivian H. Lyons is with Department of Epidemiology, University of Washington, and Harborview Injury Prevention & Research Center, Seattle.