Donald A Redelmeier1,2,3,4,5, Junaid A Bhatti1,2,3. 1. Departments of Medicine and of Surgery, University of Toronto, Toronto, Ontario, Canada. 2. Evaluative Clinical Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada. 3. Institute for Clinical Evaluative Sciences,Toronto, Ontario, Canada. 4. Division of General Internal Medicine, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. 5. Center for Leading Injury Prevention Practice Education & Research, Toronto, Ontario, Canada.