1. Health Research Development Program, Ontario Ministry of Health, Ontario, Canada; now Postdoctoral Fellow, System-Linked Research Unit on Health and Social Services Utilization, McMaster University Faculty of Health Sciences, Hamilton, Ontario
2. Pharmacy Medication Monitoring Program, Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
3. Ciba-Geigy Canada, Toronto, Ontario, Canada; now retired
4. Departments of Clinical Epidemiology and Biostatistics and of Medicine, McMaster University
5. Canadian Pharmaceutical Association, Ottawa, Ontario, Canada
6. Department of Clinical Epidemiology and Biostatistics, McMaster University
7. Statistics, and Health Economics, Ciba-Geigy USA, Summit, NJ