title: When are observational studies as credible as randomised trials?
authors.affiliation: Department of Clinical Epidemioloy, Leiden University Medical Centre, Bldg 1 C9-P, 2300 RC Leiden, Netherlands. J.P.Vandenbroucke@lumc.nl
authors.forename: Jan P
authors.initials: JP
authors.lastname: Vandenbroucke
mesh_terms: D015982:Bias; D015986:Confounding Factors, Epidemiologic; D064420:Drug-Related Side Effects and Adverse Reactions; D006801:Humans; D019370:Observation; D011897:Random Allocation; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012306:Risk