2. Appraising the relevance of results

2.3 The eight steps

2. What is the study design?

Controlled trial: an experimental study, in which an intervention is carried out on a group of subjects; the response to this intervention is compared to that of a similar group, the control, which did not receive the intervention. .

The reviewer must recognize the type of study design being applied so as to check that it is the most appropriate one for his own question. In addition, these study designs are ranked and the level of evidence (confidence level) of results varies from one model to another. The increasing level of evidence goes from the cross-sectional study, to the case-control study, to the cohort study, and to the controlled trial, for the maximum level of evidence.