1. Department of Population Medicine; Harvard Medical School and Harvard Pilgrim Health Care Institute; Boston MA USA
2. Group Health Research Institute; Seattle WA USA
3. The Permanente Medical Group; Department of Adult Medicine; San Francisco CA USA
4. Center for Health Policy and Health Services Research; Henry Ford Health System; Detroit MI USA
5. Kaiser Permanente Southern California; Department of Research and Evaluation; Pasadena CA USA
6. Center for Applied Health Research; Scott & White Healthcare jointly with Central Texas Veterans Health Care System; Temple TX USA
7. Kaiser Northern California Division of Research; Kaiser Foundation Research Institute; CA USA
8. Department of Health Services Research; University of Washington; Seattle WA USA