[1] Univ Rochester, Sch Med, Dept Anesthesiol & Perioperat Med, Rochester, NY USA
[2] Univ Rochester, Sch Med, Dept Publ Hlth Sci, Rochester, NY USA
[3] RAND, RAND Hlth, Boston, MA USA
[4] Univ Rochester, Sch Med, Dept Neurol, Rochester, NY USA
[5] Washington Univ, Dept Med, St Louis, MO USA
[6] Washington Univ, Inst Publ Hlth, Ctr Hlth Econ & Policy, St Louis, MO USA
[7] Univ Rochester, Sch Med, Dept Neurosurg, Rochester, NY USA
[8] Columbia Sch Nursing, Ctr Hlth Policy, New York, NY USA
[9] Univ Rochester, Med Ctr, 601 Elmwood Ave, Box 604, Rochester, NY 14642 USA