1. John A. Kairalla, PhD, is Assistant Professor, Department of Biostatistics, University of Florida, Gainesville
2. Sandra L. Winkler, PhD, OTR/L, is Research Health Science Specialist, James A. Haley Veterans' Hospital Center of Innovation in Disabilities and Rehabilitation Research, Tampa, FL
3. Hua Feng, MS, is Senior Biostatistician, Veterans Affairs (VA) Health Services Research & Development Center of Innovation, Michael E. DeBakey VA Medical Center, Houston, TX, and Senior Biostatistician, Department of Medicine, Baylor College of Medicine, Houston, TX