1. JK Freburger, PT, PhD, is Research Associate and Fellow, Cecil G. Sheps Center for Health Services Research, University of North Carolina, Chapel Hill, NC
2. TS Carey, MD, MPH, is Director, Cecil G. Sheps Center for Health Services Research, and Professor, Departments of Medicine and Social Medicine, School of Medicine, University of North Carolina, Chapel Hill
3. GM Holmes, PhD, is Research Associate and Fellow, Cecil G. Sheps Center for Health Services Research, University of North Carolina, Chapel Hill