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Most research starts with an idea...and a question.
The next step is to answer that question. You might presume that you jump straight into answering it by formulating a research project. But lets not re-invent the wheel. What do we already know about the question? What are the gaps?
To answer the question the best you can, you first need to know what has been asked and answered before, and this is done via a 'literature review'.
Step 1. Preparing for the Search: Reference Managers
Step 1. Preparing for the Search: Reference Managers
You're going to want to get a reference manager to store all the publications that you can find relating to the subject matter to make it (a) easier to find later (b) easier to reference when you write your manuscript.
The following are some reference managers (in no particular order):
Step 2. Choose your review type
Step 2. Choose your review type
This is where it can get a little more complicated. Do you want to have a general idea of what is (or isn't) out there to structure your own project? Or do you want to publish your review? The latter requires a bit more rigor and structures that follow international guidelines.
Depending on your question, there are a variety of reviews that you can perform:
A cursory google search and research database search (eg pubmed, dimensions or google scholar) if its a simple internal audit
An in depth semi-structured research database search
Narrative review if theres unlikely to be much evidence
Scoping review if theres a little more evidence that you can pull together
Integrative review when a lot of the evidence is in the 'grey' literature
Systematic review when theres a few Randomised Control Trials to pull together
Umbrella review when theres a few systematic reviews to pull together
Here's a list of the different approaches you can take in order of grandeur (least to most):
Rapid Review
Rapid Review
What is a rapid review?
The Cochrane Rapid Reviews Methods Group has proposed the following definition: “A form of knowledge synthesis that accelerates the process of conducting a traditional systematic review through streamlining or omitting specific methods to produce evidence for stakeholders in a resource-efficient manner.”
Rapid reviews are usually undertaken when decision makers have urgent and emerging needs which require evidence produced on a short time frame. Typically, to compensate for the short time frame of a rapid review, methodological rigour may be sacrificed. For example, the grey literature may not be sought and preference may be given to the more readily available research published and written in English.
A rapid review follows most of the principle steps of a systematic review, using systematic and transparent methods to identify, select, critically appraise and analyze data from relevant research. However, to provide timely evidence, some of the components of a systematic review process are either simplified or omitted. There are various approaches for simplifying the review components, such as by reducing the number of databases, assigning a single reviewer in each step while another reviewer verifies the results, excluding or limiting the use of grey literature, or by narrowing the scope of the review. In general, a rapid review takes about four months or less.
Adapted from: Health Evaluation and Applied Research Development (HEARD). (June 25th, 2018). Rapid reviews versus systematic reviews. https://www.heardproject.org/news/rapid-review-vs-systematic-review-what-are-the-differences/
Narrative Review
Narrative Review
A traditional literature review or narrative review examines and evaluates the scholarly literature on a topic. Literature reviews often do not answer one specific question, rather they usually bring together a summary of the literature in a qualitative manner.
A literature review may be undertaken in a systematic way in order to be comprehensive, without being a systematic review. It is important to recognise the differences between the two and determine which type of review is best suited to your needs - or whether one of the other reviews detailed here is more applicable.
Narrative reviews:
provide a (generally qualitative) summary of the relevant literature, as determined by the author.
do not necessarily provide an analysis of the literature or its quality.
usually do not include a description of the methodology of the search process.
refer to key journal literature without going into the grey literature.
don't always answer a specific research question.
are not protocol driven.
Scoping Review
Scoping Review
Scoping review
"Scoping reviews, a type of knowledge synthesis, follow a systematic approach to map evidence on a topic and identify main concepts, theories, sources, and knowledge gaps" (Tricco, et al., 2018).
"Scoping reviews conducted as precursors to systematic reviews may enable authors to identify the nature of a broad field of evidence so that ensuing reviews can be assured of locating adequate numbers of relevant studies for inclusion" (Munn, Z., Peters, M., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E., 2018).
A scoping review may be undertaken as a preliminary exercise prior to the conduct of a systematic review, or as a stand alone review.
A scoping review may be used:
As a precursor to a systematic review.
To identify the types of available evidence in a given field.
To identify and analyse knowledge gaps.
To clarify key concepts/ definitions in the literature.
To examine how research is conducted on a certain topic or field.
To identify key characteristics or factors related to a concept.
Adapted from: JBI Manual for Evidence Synthesis, chapter 11 Scoping reviews. https://doi.org/10.46658/JBIMES-20-01
Getting started:
Cochrane: Scoping reviews: what they are and how you can do them
Reporting:
The PRISMA extension for scoping reviews was published in 2018. The checklist contains 20 essential reporting items and 2 optional items to include when completing a scoping review. Scoping reviews serve to synthesize evidence and assess the scope of literature on a topic. Among other objectives, scoping reviews help determine whether a systematic review of the literature is warranted.
Systematic Review
Systematic Review
A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a given research question. Researchers conducting systematic reviews use explicit methods aimed at minimizing bias in order to produce more reliable findings that can be used to inform decision making.
An essential step in the early development of a systematic review is the development of a review protocol. A protocol pre-defines the objectives and methods of the systematic review which allows transparency of the process. It must be done prior to conducting the systematic review as it is important in restricting the presence of reporting bias. The protocol is a completely separate document to the systematic review report.
Adapted from: JBI Manual for Evidence Synthesis
In summary, a systematic review:
Addresses a specific question
Uses specified methodology
Assesses quality of the literature
Requires a team and long term commitment
Helpful links
Helpful links
Umbrella Review
Umbrella Review
Umbrella reviews are sometimes referred to as a "review of reviews". They are an attempt to identify and appraise, extract and summarise all the evidence from research syntheses related to a topic or question.
Umbrella reviews may:
Include analyses of different interventions for the same problem or condition.
Analyse the same intervention and condition, but different outcomes.
Analyse the same intervention but different conditions, problems or populations.
Umbrella reviews offer the possibility to address a broad scope of issues related to the topic of interest.
Adapted from: JBI Manual for Evidence Synthesis
In summary, an umbrella review:
Is a systematic review of systematic reviews
Synthesizes systematic reviews of the same topic
Assesses scope and quality of individual systematic reviews
Step 3. Choose your databases to search
Step 3. Choose your databases to search
You've got an idea of the type of review you want to do, so now you have to go looking for the literature! The following are free search engines to help you do a quick search of the current evidence (in order of my preference).
Check with your university for any paid engines that you may have access to via an enterprise subscription.
Pubmed is usually the go-to, but theres plenty of opinions out there with variable reasons for strengths/weaknesses
Step 4. Review Time!
Step 4. Review Time!
If you are doing this review to inform your project, you can jump straight in to the review!
If you are doing this review for publication, theres a few steps involved to start with:
Create a study protocol - PRISMA is the reporting structure that you need to use. Consider publishing it!
Register your protocol. Why register? The idea of prospective registration is to reduce bias and increase transparency (not changing protocols on the fly!)
Who should you register with?
PROSPERO is the most popular, only for reviews that involve an intervention and is free
Open Science Framework is free and has preregistration
Inplasy has a small fee, has a 48 hour turnaround and generates a DOI
Perform your review - there's a few software systems that can help (check with your university or health service for their preferred system). Here's some of my favourites:
Covidence (paid)
Analysis & Write up your review - don't forget to use the PRISMA structure and checklist
Choose a journal to publish in
Google Sites
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