It uses rigorous and explicit methods to identify, select, and critically appraise relevant research. The data extracted through this methodology are then analysed using standard statistical methods and presented in the review. In contrast to the traditional narrative reviews, systematic reviews adhere to a strict scientific design. In the case of Cochrane reviews, the design requires a comprehensive search for all available data in all languages on the topic. This helps to avoid bias in the selection of data and thus ensure greater reliability of the data to be included.
Explicit methodology is used to ensure reproducibility of results.
The methodological rigour of a systematic review is achieved by preparation of a review protocol that gives details of how the studies are going to be searched, retrieved and critically appraised before inclusion in the review. The results of a review will only be robust if the trials included are of sufficient quality. As new data become available, each Cochrane review is updated. The Cochrane systematic reviews are prepared by Collaborative Review Groups that not only ensure thorough peer review but also assist in retrieval of studies, identification of unpublished studies, and translation of studies not published in English. The Programme is collaborating with seven Collaborative Review Groups, namely those on pregnancy and childbirth, fertility regulation, infectious diseases, neonatal disorders, gynaecological cancers, sexually transmitted diseases, and effective practice and organization of care.