[1] VA Palo Alto Hlth Care Syst, Ctr Hlth Care Evaluat, Menlo Pk, CA 94025 USA
[2] Stanford Univ, Sch Med, Div Gen Internal Med, Palo Alto, CA 94304 USA
[3] Stanford Univ, Sch Med, Ctr Hlth Policy, Palo Alto, CA 94304 USA
[4] Stanford Univ, Sch Med, Ctr Primary Care & Outcomes Res, Palo Alto, CA 94304 USA
[5] VA Palo Alto Hlth Care Syst, Womens Hlth Ctr, Palo Alto, CA USA
[6] VA Palo Alto Hlth Care Syst, Hlth Econ Resource Ctr, Menlo Pk, CA 94025 USA
[7] VA Greator Los Angeles HSR&D Ctr Study Heathcare, Sepulveda, CA USA
[8] Univ Calif Los Angeles, Sch Publ Hlth, Dept Hlth Serv, Los Angeles, CA 90024 USA
[9] Stanford Univ, Sch Med, Dept Hlth Res & Policy, Palo Alto, CA 94304 USA
[10] Stanford Univ, Sch Med, Dept Pediat, Palo Alto, CA 94304 USA