1. Department of Surgery, Division of Otolaryngology-Head and Neck Surgery; Dartmouth-Hitchcock Medical Center; Lebanon
2. Data Modeling Branch, Surveillance Research Program, Division of Cancer Control and Population Sciences; National Cancer Institute; Rockville Maryland U.S.A
3. The Dartmouth Institute for Health Policy and Clinical Practice; Hanover New Hampshire U.S.A
4. VA Outcomes Group, Department of Veterans Affairs Medical Center; White River Junction; Vermont U.S.A