Systematic reviews aim to provide a comprehensive, unbiased synthesis of existing knowledge by examining “all” of the evidence relevant to a pre-determined question, and summarising into a single document, which is often used to inform practice and policy. Systematic reviews follow a highly structured research process that requires rigorous methods to ensure that the results are reliable and transparent.

The reasons for undertaking a systematic review may include:

• an identified gap in the knowledge
• conflicting results in the research literature
• to identify the effectiveness of an intervention 

Aromataris, E. and Munn, Z., 2020. 'Chapter 1: JBI Systematic Reviews', in Aromataris, E., Munn, Z., (eds.). JBI Manual for Evidence Synthesis. https://doi.org/10.46658/JBIMES-20-02

'What are systematic reviews?' by Cochrane, https://www.youtube.com/watch?v=egJlW4vkb1Y

Topic of question: clearly defined and answerable question with a narrow focus, often clinical.

Search strategy: rigorous and reproducible search statement to locate all potentially relevant material.

Time frame: can be time consuming due to rigour. Average time 12 months.

Number of reviewers: usually 2 or more.

Inclusion and exclusion criteria to review studies: explicit inclusion and exclusion criteria developed.

Higgins, J.P.T. and Green, S. (eds.), 2011. 'Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0', The Cochrane Collaboration. https://handbook-5-1.cochrane.org/

As a systematic review requires reproducible research methodology, there are clear processes and steps involved in order to produce a successful review.  These include the following:

1. Formulating a focused clear review question, often using the PICO tool 

2. Defining a plan for the review (protocol) 

3. Locating studies through searching

4. Selecting studies for inclusion and exclusion based on predefined criteria outlined in protocol

5. Extracting data from the studies

6. Assessing the quality of studies

7. Analysing and synthesising the relevant studies, often using a meta-analysis

8. Presenting and interpreting the results, potentially including a process to establish certainty in the body of evidence 

For an accessible video about the systematic review process visit https://www.youtube.com/watch?v=egJlW4vkb1Y 

'The Concept of a Systematic Review - What authors DO' by Jessica Kaufman, licensed under CC-BY-NC-SA. https://cccrg.cochrane.org/infographics

Aromataris, E. and Munn, Z., 2020. 'Chapter 1: JBI Systematic Reviews', in Aromataris, E., Munn, Z., (eds.). JBI Manual for Evidence Synthesis. https://doi.org/10.46658/JBIMES-20-02