[1] RAND Corp, Pittsburgh, PA USA
[2] RAND Corp, Dept Econ Sociol & Stat, Santa Monica, CA 90401 USA
[3] Carnegie Mellon Univ, Stat & Hlth Policy, Pittsburgh, PA 15213 USA
[4] Kaiser Permanente, Pasadena, CA USA
[5] Ctr Medicare & Medicaid Serv, Baltimore, MD USA
[6] Commonwealth Fund, Policy & Res, New York, NY USA