This guide is a work in progress and is updated with new material added on a regular basis. If you have come across a useful resource when conducting your own systematic review that you think may be useful to others, please let us know!
This is a brief introduction to systematic reviews that you may have to do in postgraduate study or your academic career.
It will not go into lots of detail as there are many online and print resources that cover this topic and which go into a lot more detail than is possible here, but this will hopefully give you some idea as to where and how to start.
Remember!
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You will find that people will often say 'systematic literature review' to describe or define the literature review process for any students and this is because all literature reviews should be conducted in a systematic fashion.
This means that when you're working out which guidelines to follow you need to think about the degree of systematic literature review you're conducting and also what level of study you're doing the review at.
Generally speaking, if you have been given an assignment--whether that's an essay, poster, or class presentation--and you're an undergraduate student then you will be doing a literature review not a systematic review (no matter what language your module handbook might use).
Sometimes, your assignment might be to do a literature review and only focus on a certain number of papers - so your lecturer might say to select e.g. 5 articles to talk about in your essay. Even when you're doing your undergraduate dissertation (aka final year project) you will still be doing a traditional literature review, not a systematic review. And it's important to be aware of the difference between them as a traditional literature review is generally conducted in a shorter timeframe (a few weeks or a couple of months) and with a limited number of databases, whereas a systematic review can take anywhere up to two years to complete, looks at a lot more resources for material, and has to have a minimum of two people involved in searching and screening the articles.
So, don't panic at the language being used to name what you've got to do: literature review, systematic review, systematic literature review, systematic review of the literature. Instead, look at the degree of what you're being asked to do: when does it have to be done by, have you been told to focus on a limited number of papers, are you doing it by yourself, do you have to limit your search to a small number of databases and so on.
If you're a postgraduate student doing a thesis then you may either be doing a traditional literature review or a systematic review. Again, don't focus on the language used to name the piece of work you have to do; examine the scope of what you're being asked to do and use that to determine if it's really a systematic review or a traditional literature review.
And if you get stuck, or you're still not sure, talk to your lecturer and your academic librarian for advice.
A systematic review is different from a literature review in a number of key ways and the table[1] below sets out these differences for you to compare.
| Systematic Review | Literature (Narrative) Review | |
|---|---|---|
| Question | Focused on one question |
Not limited to focussing on one particular question within a topic; it could be an overview of a topic in a more general way |
| Protocol | A protocol / plan which has been peer reviewed is included | No need for a protocol |
| Background / literature review | Provides a summary of the available papers on a / the topic | Provides a summary of the available papers on a / the topic |
| Objectives | Any objectives have been clearly documented | Identifying objectives is not mandatory |
| Inclusion / exclusion criteria |
Any limiting criteria have been decided on--and recorded in the plan--before the review starts |
Limiting criteria are not usually recorded but there are no restrictions on doing so (unless your academic has told you not to) |
| Search strategy |
The search strategy should be comprehensive covering key databases and other relevant resources. Separate searches should be done for each database and the search strategy and the outcomes should be recorded in a clear, systematic, and logical way to make them as repeatable as possible. |
The search strategy is not usually recorded but there are no restrictions on doing so (unless your academic has told you not to) |
| Selecting articles (process) | How articles were selected for inclusion should be clear and understandable | How articles were selected for inclusion is not usually described |
| Evaluating articles (process) | The evaluation of each study should involve a comprehensive assessment of their quality, strengths and weaknesses | An evaluation of the quality of each study might not be included. |
| Extracting key information | The process should be clear and specific so it could be followed by someone else (e.g. the 2nd person in a 2 person systematic review) | How the key information was extracted from the papers is not usually recorded in an explicit, step-by-step way |
| Results and synthesising the data |
There should be clearly written summaries which have been based on high-quality evidence. Any methods used for synthesising the data and presenting the results should be done in such a way as to minimise bias. |
Summaries can be based on papers where the quality of the studies may not have been examined. Instances of possible bias are less likely to have been dealt with |
[1] Adapted from:
Bettany-Saltikov, J. (2012) How to do a systematic literature review in nursing: a step-by-step guide. Berkshire: Open University Press.
Robert Gordon University Library, Aberdeen (2020) Systematic reviews: examining myths & misconceptions. Available from: https://library.rgu.ac.uk/c.php?g=536793&p=3673878 (Accessed: 03 August 2021)
