title: Selection bias and the relationship between APACHE II and mortality.
authors.forename: W A
authors.initials: WA
authors.lastname: Knaus
authors.forename: D P
authors.initials: DP
authors.lastname: Wagner
mesh_terms: D006801:Humans; D009026:Mortality; D011379:Prognosis; D012494:Sampling Studies; D015983:Selection Bias; D012720:Severity of Illness Index