[1] Hosp Sick Children, Child Hlth Evaluat Sci, Toronto, ON, Canada
[2] Univ Toronto, Dalla Lana Sch Publ Hlth, Div Biostat, Toronto, ON, Canada
[3] UCL, Dept Stat Sci, London, England
[4] Univ Toronto, Inst Hlth Policy Management & Evaluat, Toronto, ON, Canada
[5] Univ Toronto, Hosp Sick Children, Div Neonatol, Toronto, ON, Canada
[6] Univ Alberta, Women & Childrens Hlth Res Inst, Edmonton, AB, Canada
[7] Univ Manitoba, Winnipeg, MB, Canada
[8] Childrens Hosp, Res Inst Manitoba, Winnipeg, MB, Canada
[9] Childrens Hosp, London Hlth Sci Ctr, London, ON, Canada
[10] Schulich Sch Med & Dent, Dept Paediat, London, ON, Canada
[11] Schulich Sch Med & Dent, Dept Epidemiol & Biostat, London, ON, Canada
[12] London Hlth Sci Ctr, Childrens Hlth Res Inst, London, ON, Canada