1. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts2Massachusetts General Hospital, Boston3National Bureau of Economic Research, Cambridge, Massachusetts
2. Medical Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
3. National Bureau of Economic Research, Cambridge, Massachusetts5Leonard D. Schaeffer Center for Health Policy and Economics, University of Southern California, Los Angeles6RAND Corporation, Santa Monica, California
4. Leonard D. Schaeffer Center for Health Policy and Economics, University of Southern California, Los Angeles6RAND Corporation, Santa Monica, California