1. Division of Health Policy and Insurance Research, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts
2. Department of Medicine, Duke University School of Medicine, Durham, North Carolina
3. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts
4. Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
5. Harvard Kennedy School, Cambridge, Massachusetts
6. National Bureau of Economic Research, Cambridge, Massachusetts