1. Division of General Surgery and Trauma, Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
2. Center for Research on Health Care, Division of General Internal Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
3. Division of Acute Care Surgery, Department of Surgery, University of Rochester Medical Center, Rochester, New York
4. Center for Surgery and Public Health, Department of Health Care Policy, Brigham and Women’s Hospital, Boston, Massachusetts