1. Institute for Health Research, Kaiser Permanente Colorado, Aurora
2. Chemical Dependency Treatment Services, Colorado Permanente Medical Group, Aurora
3. Division of General Internal Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora
4. Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California
5. Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena
6. Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Institute, Marshfield, Wisconsin
7. Center for Health Systems Research, Office of Research, Denver Health and Hospital Authority, Denver, Colorado
8. Department of Epidemiology, Colorado School of Public Health, Aurora