1. Department of Health Care Policy and Management, Harvard T. H. Chan School of Public Health, Boston, Massachusetts2Division of General Internal Medicine and Primary Care, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
2. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts
3. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts4Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts5National Bureau of Economic Research, Cambridge, Massachusetts