(i) Define a focused question addressing the population, intervention, comparison (if any) and outcomes. (ii) Evaluate whether a systematic review is appropriate to answer the question. Systematic and non-systematic approaches are complementary; the former summarise research on focused topics and highlight strengths and weaknesses in existing bodies of evidence, whereas the latter integrate research from diverse fields and identify new insights. (iii) Assemble a team and write a study protocol. (iv) Search for eligible studies using multiple databases (MEDLINE alone is insufficient) and other resources (article reference lists, author files, content experts). Expert assistance is helpful. (v) Decide on the inclusion or exclusion of each identified study, ideally in duplicate, using explicitly defined criteria. (vi) Abstract key information (including on study design, participants, intervention and comparison features, and outcomes) for each included article, ideally in duplicate. (vii) Analyse and synthesise the results by narrative or quantitative pooling, investigating heterogeneity, and exploring the validity and assumptions of the review itself. In addition to the seven key steps, the authors provide, information on electronic tools to facilitate the review process, practical tips to facilitate the reporting process and an annotated bibliography.