A proper systematic review looks at absolutely every resource to find all the information to answer a very narrow research question.
What's in a name?
The difference between a systematic review and a literature review and why it matters.
| Feature | Systematic Review | Literature Review |
|---|---|---|
| Definition | High level overview of primary research on a focused question that identifies, selects and synthesises, and appraises, all high quality research evidence relevant to that question |
Qualitatively summarises evidence on a topic using informal or subjective methods to collect and interpret studoes |
| Goals | ||
| Question | ||
The table above (1) shows the extra level of complexity needed to complete a systematic review including needing multiple authors to help avoid bias in screening and use of statistical analysis resources to enable meta-analysis of all the relevant results. A systematic review needs to:
- Have found all the data available to answer the focussed research question.
- Have aimed to minimise bias by using explicit, systematic methods that are documented in advance with a protocol and then recorded in the review using the PRISMA flowchart (2).
- The undertaking of the review should be transparently recorded, including publishing the search strategies, so that the results can be verified or reproduced.
The University of Pittsburgh HSLS Systematic Review Program gives more details about what is involved in a systematic review, including the timeline suggested by the Cochrane Handbook (3).
Often when people say they have completed a systematic review they just mean that they have searched more than one database systematically. Although this isn’t a ‘proper’ systematic review, there is still academic value in doing this. It means that they have made a thorough search strategy, which can be reproduced by other researchers, and used this in several databases to find many resources that provide the evidence to support their argument.
A typology of reviews: an analysis of 14 review types and associated methodologies by Grant and Booth provides a good description of the different types of review that can be written. (4)
If you are going to be doing a ‘proper’ systematic review then it may be worth you completing this free CourseEra online course from John Hopkins University. (5) It takes approximately 14 hours to complete and covers how to formulate an answerable research question, define inclusion and exclusion criteria, search for the evidence, extract data, assess the risk of bias in clinical trials, and perform a meta-analysis.
You may also find it useful to look at our reading list where we collect links to useful handbooks, articles and books that explain the process of doing a systematic review.
There is also a Microsoft Teams site which aims to be a Community of Practice for those engaging in systematic reviews to get advice and support from others involved in the same process. The site is being developed as a pilot scheme by the Imperial College London Medicine Liaison Librarians but we are hoping to attract people from across the College, and its collaborators, who have experience of systematic reviews, as well as those who are new to the process. The Librarians can offer support and advice, especially about the searching part of the process, but are not experts in other areas such as meta-analysis and statistics. The aim of this site is to provide a community space for researchers to receive and offer support to each other as systematic reviews are conducted. To join, click on ‘join or create a team’ on the main Imperial College London Teams page and search for ‘systematic.’ Alternatively, please email lib-med-liaison@imperial.ac.uk and ask to be added.
If you have any questions about this stage of the process your subject librarian will be happy to help. Our subject support page lists the medical librarian for each campus (6) or book a research consultation at a time convenient for you using our online booking form. (7)
Return to the Systematic Review Flowchart