title: Probability of adverse events that have not yet occurred: a statistical reminder.
abstract: The probability of adverse and undesirable events during and after operations that have not yet occurred in a finite number of patients (n) can be estimated with Hanley's simple formula, which gives the upper limit of the 95% confidence interval of the probability of such an event: upper limit of 95% confidence interval = maximum risk = 3/n (for n > 30). Doctors and surgeons should keep this simple rule in mind when complication rates of zero are reported in the literature and when they have not (yet) experienced a disastrous complication in a procedure.
authors.affiliation: II Department of Surgery, University of Cologne, Kliniken der Stadt Köln, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Eypasch
authors.forename: R
authors.initials: R
authors.lastname: Lefering
authors.forename: C K
authors.initials: CK
authors.lastname: Kum
authors.forename: H
authors.initials: H
authors.lastname: Troidl
mesh_terms: D016001:Confidence Intervals; D006801:Humans; D007431:Intraoperative Complications; D011336:Probability; D012306:Risk