[1] Harvard Univ, Sch Publ Hlth, Dept Hlth Policy Management, Boston, MA 02115 USA
[2] Brigham & Womens Hosp, Div Gen Med, Sect Hlth Policy, Boston, MA 02115 USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA USA
[4] RAND Corp, Santa Monica, CA USA
[5] NIH, Dept Clin Bioeth, Warren Grant Magnuson Clin Ctr, Bethesda, MD 20892 USA