1. Interfaculty Initiative in Health Policy, Harvard University, Cambridge, Massachusetts.
2. Micheli Center for Sports Injury Prevention, Boston Children's Hospital, Boston, Massachusetts.
3. Division of Sports Medicine, Boston Children's Hospital, Boston, Massachusetts.
4. University of Washington, Department of Pediatrics, Seattle, Washington.
5. Seattle Children's Research Institute, Center for Child Health, Behavior and Development, Seattle, Washington.
6. Harborview Injury Prevention and Research Center, Seattle, Washington.
7. Chronic Traumatic Encephalopathy Center, Boston University, Boston, Massachusetts.
8. Brain Injury Center, Boston Children's Hospital, Boston, Massachusetts.