A systematic review is a literature review that gathers together the results of primary research to answer a specific research question. It is done in a systematic and scientific way. It should identify, select, synthesize and appraise all the high-level research evidence related to the research question. 

Usually a systematic review involves creating a research methodology of how searches are to be performed in a systematic, repeatable way. The purpose is to locate as many relevant research articles as possible using the pre-set selection criteria. The results can then be looked at either quantitatively or qualitatively. In a quantitative review, critical analysis is performed on the articles and also the results as a whole. This can result in highlighting the effect of a variable comprehensively. In a qualitative review, the themes and results focused around the topic are highlighted. The overall analysis is used to explain the ways the field can be improved and how it can be done. 

Systematic reviews typically take a long time to complete. Researchers use systematic methods in order to minimize bias. This produces more reliable findings, which can lead to more informed decision making. 

Eight steps to create a systematic review:

1. Assemble the team of people who will conduct the systematic review. 
2. Develop the clinical question. 
3. Write the protocol to help plan and outline the study methodology. 
4. Source the literature by conducting a comprehensive search with a search strategy that is explicit and reproducible. 
5. Evaluate the results.
6. Assess for quality and bias within the results. 
7. Extract the data
8. Write the review by documenting the search process, preparing a comprehensive report of all the steps involved during the process and present the results.