1. RAND Health, Santa Monica, California
2. Department of Pediatrics, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California
3. Division of General Internal Medicine, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angles, California
4. Department of Health Services, School of Public Health, University of California, Los Angeles, Los Angeles, California
5. Department of Pediatrics, University of California, San Francisco, San Francisco, California
6. University of California, Los Angeles, Los Angeles, California