title: Misclassification of hospital procedure volume in surgical outcomes studies.
authors.forename: D R
authors.initials: DR
authors.lastname: Urbach
mesh_terms: D017052:Hospital Mortality; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D006278:Medicare; D010179:Pancreas / Q000601:surgery*; D014481:United States