1. Division of Pediatric Medicine and the Pediatric Outcomes Research Team (PORT), Child Health Evaluative Sciences Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
2. Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
3. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
4. Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
5. The Applied Health Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.