Affiliation: | 1. Division of Emergency Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada;2. Department of Surgery, School of Medicine, University of Auckland, Auckland, New Zealand;3. Division of Emergency Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada ICES (formerly known as the Institute for Comparative and Evaluative Sciences), Toronto, Ontario, Canada Biostatistics Research Unit, Toronto General Hospital, Toronto, Ontario, Canada;4. ICES (formerly known as the Institute for Comparative and Evaluative Sciences), Toronto, Ontario, Canada;5. Biostatistics Research Unit, Toronto General Hospital, Toronto, Ontario, Canada;6. Department of Emergency Medicine, UCSF, San Francisco, California, USA;7. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts, USA Division of General Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA |