title: [Sequential analysis in clinical and epidemiological research].
abstract: In clinical trials and epidemiological studies, interim analyses are usually performed for ethical or economical reasons, although efficiency aspects can also be a reason. The analysis is referred to as group-sequential analysis or continuous-sequential analysis, dependent on the number of interim analyses performed. Repeated testing of cumulative data requires an adjustment to the significance level or type I error alpha of a statistical test. On average a (group-)sequential analysis of a clinical or epidemiological study requires less patients than the analysis of a fixed-sample study.
authors.affiliation: Universiteit Utrecht, Centrum voor Biostatistiek, Postbus 80.058, 3508 TB Utrecht. i.vandertweel@bio.uu.nl
authors.forename: I
authors.initials: I
authors.lastname: van der Tweel
authors.forename: M
authors.initials: M
authors.lastname: Schipper
mesh_terms: D002986:Clinical Trials as Topic; D003627:Data Interpretation, Statistical; D016021:Epidemiologic Studies; D006801:Humans; D012107:Research Design; D018401:Sample Size