1. Department of Health Sciences, Brock University, St Catharines, Ontario, Canada
2. Department of Public Health, Erasmus MC University Medical Center, Rotterdam, the Netherlands
3. Department of Radiology, Stanford University School of Medicine, Palo Alto, California
4. Institute for Technology Assessment, Massachusetts General Hospital, Harvard Medical School, Boston
5. Department of Medicine, Stanford University School of Medicine, Palo Alto, California
6. School of Public Health, University of Michigan, Ann Arbor
7. Information Management Systems, Rockville, Maryland
8. Department of Epidemiology, University of Michigan, Ann Arbor