1. Pharmaceutical Outcomes Research & Policy Program, University of Washington, Box 357630, Seattle, WA 98195-7630, USA
2. Department of Biomedical Informatics & Medical Education, University of Washington, Box 358047, Seattle, WA 98195-7630, USA
3. Department of Health Services, University of Washington, Box 357162, Seattle, WA 98195-7630, USA
4. Department of Epidemiology, University of Washington, Box 357236, Seattle, WA 98195-7630, USA
5. Department of Biostatistics, University of Washington, Box 357232, Seattle, WA 98195-7630, USA