1 From the Kaiser Permanente Center for Effectiveness and Safety Research, Pasadena, CA (E.A.M.); RAND, the Division of General Medicine and Primary Care, Brigham and Women's Hospital, and the Department of Health Policy and Management, Harvard School of Public Health- all in Boston (E.C.S.); and the Veterans Affairs Center for Clinical Management Research, Veteran Affairs Ann Arbor Healthcare System, and the University of Michigan Medical School and Institute for Healthcare Policy and Innovation - all in Ann Arbor (E.A.K.).