1. Department of Emergency Medicine; The University of British Columbia; 855 West 12 Avenue Vancouver British Columbia V5Z 1 M9 Canada
2. Centre for Clinical Epidemiology & Evaluation; Vancouver Coastal Health Research Institute; 900 West 10 Ave Vancouver British Columbia V5Z 1 M9 Canada
3. School of Population and Public Health; The University of British Columbia; 2206 E Mall Vancouver BC V6T 1Z9
4. Department of Emergency Medicine; Faculty of Medicine, University of Ottawa; 1053 Carling Ave., E-Main Room EM-206, Box 227 Ottawa Ontario K1Y 4E9
5. Ottawa Hospital Research Institute; 725 Parkdale Ave. Ottawa ON K1Y 4E9
6. Departments of Emergency Medicine, and of Biomedical & Molecular Sciences; Queen's University; c/o 76 Stuart Street Kingston ON K7L 2 V7
7. Department of Family Medicine; University of Alberta; 8215-112 Street NW, Room 1706 College Plaza Edmonton Alberta
8. Department of Emergency Medicine, Faculty of Medicine; University of Calgary; Rockyview General Hospital, HCAC building, 7007 14 St. SW Calgary AB T2V 1P9
9. Department of Statistics; The University of British Columbia; 3182 Earth Sciences Building, 2207 Main Mall Vancouver BC V6T 1Z4 Canada
10. Department of Emergency Medicine, Faculty of Medicine and Dentistry and School of Public Health; University of Alberta; 1G1.42 Walter Mackenzie Building Edmonton AB T6G 2B7
11. School of Health Policy and Management; York University; 4700 Keele St. Toronto ON M3J 1P3
12. Emergency Department; University Health Network; 190 Elizabeth St. Toronto ON M5G 2C4
13. Public Health Medicine, Norwich Medical School; University of East Anglia; Norwich Research Park Norwich Norfolk NR4 7TJ United Kingdom