A systematic review collects and analyzes all evidence that answers a specific research question. In a systematic review, a question needs to be clearly defined and have inclusion and exclusion criteria. In general, specific and systematic methods selected are intended to minimize bias. This is followed by an extensive search of the literature and a critical analysis of the search results. The reason why a systematic review is conducted is to provide a current evidence-based answer to a specific question that in turn helps to inform decision making. Check out the Centers for Disease Control and Prevention and Cochrane Reviews links to learn more about Systematic Reviews.
A systematic review can be combined with a meta-analysis. A meta-analysis is the use of statistical methods to summarize the results of a systematic review. Not every systematic review contains a meta-analysis. A meta-analysis may not be appropriate if the designs of the studies are too different, if there are concerns about the quality of studies, if the outcomes measured are not sufficiently similar for the result across the studies to be meaningful.
Centers for Disease Control and Prevention. (n.d.). Systematic Reviews. Retrieved from https://www.cdc.gov/library/researchguides/sytemsaticreviews.html
Cochrane Library. (n.d.). About Cochrane Reviews. Retrieved from https://www.cochranelibrary.com/about/about-cochrane-reviews
Source: Kysh, Lynn (2013): Difference between a systematic review and a literature review. [figshare]. Available at: https://figshare.com/articles/Difference_between_a_systematic_review_and_a_literature_review/766364
Below is a list of databases that can be searched for systematic reviews.
General tips for evaluating systematic reviews:
- Is the question clearly stated?
- Does it outline search criteria? (e.g. databases searched, search strategies used)
- Does the study explain inclusion and exclusion criteria (e.g. studies identified through searches, studies excluded)?
This explains selection bias.
- Were the characteristics of all the studies outlined (ranges of characteristics: age, sex, race etc.)?
- Is the conclusion the authors made supported by the data in the review?
Use this rating tool to evaluate the quality of systematic reviews (https://www.ncbi.nlm.nih.gov/books/NBK242394/)