1. Health Economics Research, Inc, Waltham, Mass (J.B.M., C.J.A.); Center for Clinical Evaluation Sciences, Emory University, Atlanta, Ga (D.J.B.); Department of Health Sciences Research, Mayo Clinic, Rochester, Minn (J.P.W.); Departments of Medicine and Community and Family Medicine (G.P.S.) and Center for Health Policy Research and Education (G.P.S., D.B.M.), Duke University, Durham, NC; and Department of Veterans Affairs, Center for Health Services Research in Primary Care, Durham, NC (G.P.S.).