1. Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts2Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts5National Bureau of Economic Research, Cambridge, Massachusetts
2. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts3Division of General Medicine and Primary Care, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts4Partners Healthcare System, Boston, Massachusetts
3. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts3Division of General Medicine and Primary Care, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts