1. Division of Pediatric Medicine
2. Pediatric Outcomes Research Team, Hospital for Sick Children, Toronto, Ontario, Canada
3. Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
4. Child Health Evaluative Sciences, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
5. Health Information and Research Division, Statistics Canada, Ottawa, Ontario, Canada
6. Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada
7. Bloorview Research Institute, Bloorview Kids Rehab, Toronto, Ontario, Canada