Received from the Harvard Community Health Plan; the Division of Clinical Epidemiology, Department of Medicine, Brigham and
Women’s Hospital, Harvard Medical School; and the Department of Health Policy and Management, Harvard School of Public Health,
Boston, Massachusetts.
Presented in part at the annual meeting of the Society of General Internal Medicine, Seattle, Washington, April 30–May 2,
1991.
Supported in part by the Harvard Community Health Plan Foundation, Inc.