title: Nonrandom selection and the attributable cost of surgical-site infections.
authors.forename: Frances
authors.initials: F
authors.lastname: Birrell
authors.forename: Nicholas
authors.initials: N
authors.lastname: Graves
mesh_terms: D015986:Confounding Factors, Epidemiologic; D003428:Cross Infection / Q000191:economics* / Q000453:epidemiology; D017721:Hospital Costs; D006801:Humans; D012044:Regression Analysis; D015983:Selection Bias; D012720:Severity of Illness Index; D013530:Surgical Wound Infection / Q000191:economics* / Q000453:epidemiology