What is a Systematic Review


The Cochrane Handbook for Systematic Reviews defines a systematic review as 'an attempt to collate all empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. It uses explicit, systematic methods that are selected with a view to minimizing bias, thus providing more reliable findings from which conclusions can be drawn and decisions made. The key characteristics of a systematic review are:

   - a clearly stated set of objectives with pre-defined eligibility criteria for studies;

   - an explicit, reproducible methodology;

    - a systematic search that attempts to identify all studies that would meet the eligibility criteria;

    - an assessment of the validity of the findings of the included studies, for example through the assessment of risk of bias; and

    - a systematic presentation, and synthesis, of the characteristics and findings of the included studies.'

(Cochrane Handbook for Systematic Reviews of Interventions, Version 6.3, 2022)


Forming your Team of Reviewers

- Your Systematic Review Team should consist of a minimum of 3 reviewers, although a higher number of team members is preferable since this will speed up the screening process during the review.

- Depending on the amount of literature available on your chosen topic, you may want to consider the addition of more team members. A team of up to ten or twelve people isn't unusual for large scale systematic reviews.

- Ideally members of the team should be subject experts on the topic being researched.

- It may be beneficial to have a statistician as a member of the team if the research involves the analysis of quantitative data.

Note:  It's usually a good idea to define roles and expectations of group members early in the review process.



How long does a Systematic Review take?

"The amount of time it takes to do a systematic review can vary. Due to its research-intensive nature, it generally takes between six to eighteen months to complete a Systematic Review". DistillerSR 2023



Systematic Reviews Vs Literature Review:


There are many types of research reviews and for this reason, it's important that you and your team know what type of review is necessary for your particular study. The Covidence website explains in detail the key differences between Rapid Reviews, Scoping Reviews, Evidence Gap maps, Living Systematic Reviews,

Systematic Reviews and Literature Reviews are two of the more popular types of reviews and while they have similarities, they are not the same.

Literature reviews tend to answer broad and descriptive research questions. Systematic reviews seek to be more comprehensive and precise because they seek to answer a specific research question.

While literature reviews may require only a limited quantity of source material perhaps sourced from one or two library databases, systematic reviews require more comprehensive efforts to locate evidence. Multiple databases are usually searched, each with a specifically tailored search strategy. Apart from databases, the systematic review utilises other relevant sources including books, journals, grey literature etc.

The key differences between a Systematic Review and a Literature Review are as follows:


Systematic Review

Literature Review

Question Focused on a single question. Not necessarily focused on a single question but may describe an overview.
Protocol A peer review protocol or plan is included. No protocol is included.

Provides a summary of the available literature on a topic.


Also provides a summary of the available literature on a topic.


Objectives Clear objectives are identified. Objectives may or may not be identified.
Inclusion and exclusion criteria Criteria stated before the review is conducted. Criteria not specified.
Search strategy Comprehensive search conducted in a systematic way. Strategy not explicitly stated
Process of selecting articles Usually clear and explicit. Not described in a literature review.
Process of evaluating articles Comprehensive evaluation of study quality. Evaluation of study quality may or may not be included.
Process of extracting relevant information Usually clear and specific.

The process of extracting relevant information is not explicit and clear.

Results and data synthesis Clear summaries of studies based on high quality evidence. Summary based on studies where the quality of articles may not be specified. May also be influenced by the reviewer’s theories, needs and beliefs.

Written by a group of experts with a detailed and well-grounded knowledge of the issues.


Usually written by an individual composing a thesis, dissertation, or research paper. The completed literature review situates the individual's research within the existing body of knowledge.


Excerpt from 'Write a literature review: Literature review vs.Systematic review' by DKIT Library (March 2023)


- Example of a Literature Review Title - Big data in tourism research: A literature review

- Example of a Systematic Review Title - Big data analytics in healthcare − A systematic literature review and roadmap for practical implementation


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