1. Department of Emergency Medicine, Harbor-UCLA Medical Center, Torrance, California
2. Division of General Internal Medicine and Health Services Research, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
3. Fielding School of Public Health, Department of Health Policy and Management, University of California, Los Angeles
4. Perelman School of Medicine, Center for Emergency Care Policy and Research, Department of Emergency Medicine, University of Pennsylvania, Philadelphia
5. Leonard Davis Institute for Health Economics, Wharton School, University of Pennsylvania, Philadelphia
6. VA Greater Los Angeles Healthcare System, Los Angeles, California