He graduated from Columbia University’s College of Physicians and Surgeons, completed a medical residency at Highland Hospital in Oakland, California, and a fellowship in General Internal Medicine at Harvard. His research focuses on access to medical care, quality of care in for-profit settings, medical bankruptcy, the administrative costs of medical care, and the feasibility of national health insurance. He has authored or co-authored more than 100 journal articles and three books. He co-founded Physicians for a National Health Program.