[1] Childrens Hosp Eastern Ontario, Inst Res, Chalmers Res Grp, Dept Pediat, Ottawa, ON K1H 8L1, Canada
[2] Univ Ottawa, Dept Pediat, Ottawa, ON K1N 6N5, Canada
[3] Univ Ottawa, Dept Epidemiol & Community Med, Ottawa, ON K1N 6N5, Canada
[4] Univ Ottawa, Dept Psychiat, Ottawa, ON K1N 6N5, Canada
[5] Canadian Patient Safety Inst, Edmonton, AB, Canada
[6] McGill Univ, Montreal Childrens Hosp, Resp Med Div, Montreal, PQ H2W 1S4, Canada
[7] Univ Ottawa, Dept Epidemiol & Community Med, Ottawa, ON K1N 6N5, Canada
[8] Canadian Coordinating Off Hlth Technol Assessment, Ottawa, ON, Canada