1. VA Boston Healthcare System, Boston, Massachusetts
2. Department of Anesthesiology, Tufts University School of Medicine, Boston, Massachusetts
3. Center for Healthcare Organization and Implementation Research, Bedford VA Medical Center, Bedford, Massachusetts
4. Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
5. Health Economics Resource Center, Palo Alto, Veterans Affairs Medical Center, Palo Alto, California
6. Department of Surgery, Stanford University School of Medicine, Palo Alto, California
7. Center for Healthcare Organization and Implementation Research, VA Boston Healthcare System, Boston, Massachusetts
8. Department of Surgery, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts