1. Group Health Research Institute; Seattle Washington
2. Department of Biostatistics; University of Washington; Seattle Washington
3. Department of Epidemiology and Biostatistics; University of California at San Francisco; San Francisco California
4. General Internal Medicine Section; Department of Veterans Affairs; University of California at San Francisco; San Francisco California
5. Department of Hematology/Oncology; University of Vermont College of Medicine; Burlington Vermont
6. Department of Family Medicine; University of Vermont College of Medicine; Burlington Vermont
7. Department of Radiology; University of Vermont College of Medicine; Burlington Vermont
8. Division of Biostatistics; Department of Public Health Sciences; School of Medicine; University of California at Davis; Davis California