Читать книгу The Pocket Guide to Critical Appraisal - Iain K. Crombie - Страница 24

RCTs are always concerned with effectiveness. The key element of this design is that patients are randomly allocated to receive a new treatment or to the conventional one (or a placebo). The outcome of the new treatment is compared with that of the conventional one, identifying which is superior. RCTs are also concerned with the side effects of treatments. Most RCTs compare two treatments, but sometimes more than two treatments can be investigated. This adds complexity to the conduct and analysis of the study, although the resulting study is a valid RCT.