[1] Northwestern Univ, Feinberg Sch Med, Dept Surg, Surg Outcomes & Qual Improvement Ctr, 633 N St Clair St,20-038, Chicago, IL 60611 USA
[2] Amer Coll Surg, Div Res & Optimal Patient Care, Chicago, IL USA
[3] Univ Wisconsin, Dept Surg, Wisconsin Surg Outcomes Res Program, Sch Med, Madison, WI USA
[4] Univ Wisconsin, Dept Surg, Sch Med, Madison, WI USA
[5] Amer Coll Surg, Chicago, IL USA
[6] Univ Chicago, Dept Surg, Chicago, IL USA
[7] Amer Board Surg, Philadelphia, PA USA
[8] Accreditat Council Grad Med Educ, Chicago, IL USA
[9] Northwestern Univ, Feinberg Sch Med, Ann Robert H Lurie Childrens Hosp, Div Pediat Surg, Chicago, IL USA