From RAND Health, Santa Monica, Calif. (S.A.B., S.H.B., N.D., A.A.L., J.W.S., S.C.M., M.F.S.); the Veterans Affairs San Diego Healthcare System, San Diego, Calif., and the University of California at San Diego, La Jolla (S.A.B.); the University of California at Los Angeles (A.A.L., M.F.S.); the National Opinion Research Center, Chicago (M.R.F., C.-A.E.); Baruch College, City University of New York, New York (M.R.F.); Project Hope, Bethesda, Md. (M.L.B.); and the Agency for Health Care Policy and Research, Rockville, Md. (D.L.). Address reprint requests to Dr. Bozzette or Dr. Shapiro, HCSUS Office, RAND, 1700 Main St., Santa Monica, CA 90407-2138.for the HIV Cost Services Utilization Study Consortium.