According to Gopalakrishnan and Ganeshkumar (see full reference in the list below) a systematic review is a summary of the medical literature that uses explicit and reproducible methods to systematically search, critically appraise, and synthesize on a specific issue. It synthesizes the results of multiple primary studies related to each other by using strategies that reduce biases and random errors.

If you want to learn more about systematic reviews, please check the following resources: