Difference Between a Systematic Review and Meta Analysis
3 min read
It is a common misconception that meta-analysis and systematic reviews are the same and the terms are oft used interchangeably. While there is substantial overlap betwixt the two they are non the same affair. Let's start by defining the 2 concepts:
A systematic review is a detailed, systematic and transparent means of gathering, appraising and synthesising show to answer a well-defined question.
A meta-analysis is a statistical procedure for combining numerical information from multiple separate studies. A meta-assay should merely e'er be conducted in the context of a systematic review.
The hallmark of systematic reviews is that they seek to reduce bias at all stages of the review process. Reviews registered with organisations such as Campbell and Cochrane are specially reliable, as all authors are required to adhere to the same loftier standards of conduct and reporting. The stages in conducting a review are:
- Define your question and ideally annals your proposed review title with Campbell or similar
- Specify and publish your proposed methodology in advance in the form of a protocol
- Bear a thorough search of the literature
- Screen your search results confronting your pre-specified selection criteria to identify included studies
- Assess the quality of studies constitute
- Synthesise the evidence, this is where meta-analysis may or may non come up in
- Publish and disseminate your review
- Update the review equally new evidence is produced
Y'all can see that a systematic review involves much more than just putting the numbers together. It is a detailed, transparent and sometimes (often) time consuming process.
Why would a systematic review not include a meta-assay?
Systematic reviews volition often, but not always, contain a meta-analysis of numerical information from the included studies. Meta-assay would be a poor choice if your review question is better answered with qualitative data, such as "How adequate are psychosocial interventions for maltreated children" or "how do self-help group programs impact on women'due south empowerment?"
Conducting a meta-analysis would exist a bad thought if your studies are as well dissimilar to combine. Imagine you are conducting a systematic review on the outcome of listening to music while studying on children's exam functioning and yous find ane study on classical music, ii on pop music including primary school children and teenagers respectively, some other on death metal and a fifth on fourscore's synth classics. Would you lot combine these in a unmarried meta-analysis or would yous decide that the interventions (music blazon) and populations (age of children) are too dissimilar to combine and opt for a narrative synthesis instead? Deciding which studies you lot can and cannot combine in a meta-analysis will depend on the question you lot are asking and you lot should define the procedure for deciding in advance in your review protocol.
Conducting a meta-analysis may not always be sensible – fifty-fifty if you set out to do i. By specifying your approach to meta-analysis in advance, you tin can reduce the possibility of introducing bias and avoid making decisions retrospectively based on the studies or results you notice. This is why spending fourth dimension on your protocol and thinking through the analytic arroyo before commencement your systematic review is time well spent.
Tip 1: Beware of meta-analyses that do not follow a systematic and transparent procedure for identifying and selecting which studies to include in analysis
Tip two: When developing a systematic review title focus on the question you really want to answer, at that place is no need to constrain yourself to numerical information that can be meta-analysed.
Tip 3: Specify your analysis program in accelerate and be transparent in reporting your methods. Post-obit the appropriate reporting guidelines (PRISMA) and standards (MECCIR) is an piece of cake style to keep you right.
Tip iv: Thinking of conducting a systematic review? Contact the states for communication and back up to acquit a Campbell Systematic Review.
Blog post written by Jennifer Hanratty
Source: http://meta-evidence.co.uk/difference-systematic-review-meta-analysis/
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