1. Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada;
2. Division of Pediatric Medicine, Hospital for Sick Children, and
3. Departments of Pediatrics and
4. Health Policy, Management, and Evaluation, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada;
5. Dartmouth Institute for Health Policy and Clinical Practice, Hanover, New Hampshire; and
6. Department of Pediatrics, Dartmouth Medical School, Hanover, New Hampshire