[For the critical reader: questions to ask about randomised trials].

The aim of this article is to provide guidance for the assessment of articles on randomised trials. This guide is intended for those who may want to apply the published results of randomised trials in everyday medical practice. In order to be able to attribute the observed differences in health outcomes between treatment groups with due certainty to the treatment being evaluated, it is necessary that the groups are comparable at the start of the study, during the study, and at the end of the study, i.e. when measuring the outcomes. In order to interpret the results of randomised trials and generalise these results to clinical practice, it is also necessary to consider the purpose of the study, the comparison that is made, the magnitude and direction of the observed effect, and to whom that effect applies.