1. Division of General Medicine, University of Michigan Health Systems, Department of Health Management and Policy, University of Michigan School of Public Health, and Health Services Research and Development Unit, Ann Arbor Veterans Affairs Medical Center, Ann Arbor, Michigan, Harvard Center for Risk Analysis, Harvard School of Public Health, Boston, Massachusetts,
2. Harvard Center for Risk Analysis, Harvard School of Public Health, Boston, Massachusetts
3. Columbia University, School of Nursing, New York, New York