title: [General requirements for study designs].
abstract: It is the purpose of this review to outline the principles of biometric methods in clinical research. Several study designs such as cohort studies, case-control studies or randomized controlled trials are explained in detail, and their problems and their interpretation are discussed. It is demonstrated that observational studies may yield valuable information about associations between exposure and outcome variables but that only properly designed randomized clinical trials of adequate sample size make it possible to answer research questions about causal relationships. It is emphasized that good clinical research depends on properly designed studies more than on complicated statistical procedures.
authors.affiliation: Abteilung für Medizinische Biometrie, Universität Heidelberg.
authors.forename: H J
authors.initials: HJ
authors.lastname: Trampisch
authors.forename: J
authors.initials: J
authors.lastname: Windeler
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods / Q000592:standards*; D004812:Epidemiologic Methods; D006801:Humans
vernacular_title: Allgemeine Anforderungen an Studiendesigns.