1. Kalamazoo Area Mathematics and Science Center and
2. Interdisciplinary Health Science PhD Program, College of Health and Human Services, Western Michigan University, Kalamazoo, Michigan;
3. Center for Injury Research and Policy, Research Institute at Nationwide Children's Hospital, Columbus, Ohio; and
4. Department of Pediatrics, College of Medicine, and Division of Epidemiology, College of Public Health, Ohio State University, Columbus, Ohio