Scoping Reviews

What is a Scoping Review? A scoping review is a type of evidence synthesis which is extremely useful to locate and map available literature. Scoping reviews are exploratory in their nature and they are used for various purposes including:

-To identify the types of available evidence in a given field -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 -As a precursor to a systematic review -To identify and analyse knowledge gaps (Pg. 2. Munn et al., 2018) -Scoping reviews seem to have been described first by Nicholas Mays and colleagues (2001):

“Scoping studies aim to map rapidly the key concepts underpinning a research area and the main sources and types of evidence available, and can be undertaken as standalone projects in their own right, especially where an area is complex or has not been reviewed comprehensively before” pg. 194

And the methods were described in the seminal paper by Arksey and O’Malley (2005). Scoping reviews may also be described by other terms including scoping study, mapping of research, scoping exercise method. However, we will refer to the method as a Scoping Review.

What is the difference between a scoping review and a systematic review? There are a few key differences between systematic reviews and scoping reviews. First, systematic reviews will typically begin with a targeted research question whereas a scoping review will typically address broader topics. Second, a systematic review will typically define and limit the number of included study designs at protocol stage while a scoping review may not. Third, a systematic review is more likely to assess the quality of the included studies, whereas this is less of a priority for a scoping review whose primary objective is to map the concepts which underpin a field. Fourth, systematic reviews are often able to conduct meta-analysis on the included studies whereas the broad nature of scoping reviews and the heterogeneity of included studies make meta-analysis less possible. Finally, it might be helpful to think of scoping reviews as a hypothesis generating exercise, while systematic reviews can be used to test hypotheses.

How to conduct and report a Scoping Review: The updated Joanna Briggs Institute (JBI) Scoping Review Chapter (2020) is now available and accessible via the JBI reviewer’s manual.

This Chapter provides additional and more detailed information on the methods summarised below.

Step one – Protocol

Conduct: Before starting a scoping review, it is useful to develop a protocol or write down the research plan. This will allow the review team to predetermine the methods and objectives of the review and reduce possible bias in the research process.

Report: If a protocol is developed, review teams should indicate where this can be accessed. Some journals, will publish protocols and so will open-access repositories like Figshare or the Open Science Framework.

Step two – Research question

Conduct: Next it is necessary to formulate the research question which will be used to inform the eligibility criteria.

Report: The research question should be clearly stated in the title and eligibility criteria should be clearly described. A useful framework to use for this is the PCC criteria. This allows you to include studies with relevant population, concept, and context

Step three – Searching

Conduct: To locate relevant studies, review teams should search more than one database. The search strategy should be comprehensive and developed in consultation with a librarian. Check the quality of the search strategy by using the PRESS checklist (McGowan et al., 2016).

Report: It is best practice to describe all information sources including the interface used and any limits applied to the search.

Step four – Screening

Conduct: Studies should be selected through the application of eligibility criteria which are typically defined by the research question. Pilot testing of the screening tool is recommended in the JBI guidance to reduce errors across the review team.

Report: The process of selecting the included studies and resolving disagreements should be described. If two or more independent reviewers screen studies, it is also useful to include a measure of agreement (such as Kappa).

Step five – Data Charting

Conduct: Data extraction is called ‘data charting’ in scoping reviews (Arksey and O’Malley, 2005) and describes the process of selecting the information most able to answer the research question and inputting this information to a form.

Report: When charting the evidence from included studies, authors should describe the variables extracted and the type of form used to store this information.

Step six – Results

Conduct: In the results section of a scoping review authors should present a summary of included research and how the data answers the research question.

Report: Authors should describe how the information was located, selected (ideally presented using a PRIMSA flow diagram) summarised, and presented.

Step seven – Conclusions

Conduct: Authors should make clear recommendations for further research based on the gaps in evidence.

Report: Scoping review authors are best placed to assess the evidence base and ascertain where knowledge gaps exist. Using the results from the scoping review, authors should make clear and explicit recommendations for future research.

PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) checklist A PRISMA extension for Scoping reviews has been developed by a 24-member panel (Tricco et al., 2018) and is useful for understanding the important items to include and report in Scoping reviews, the key concepts, and the relevant terminology to use. The checklist includes 20 items and a further two optional items.

The PRISMA-ScR team have created useful supplements to the statement and checklist including a short animation and tip sheets which are available here.

Handy tip sheets for the PRISMA-ScR are available Top Tips Top tip 1: Register your protocol and stick to the plan.

Top tip 2: Always include “scoping review” in your title. This makes it easier to find and will also help you locate existing scoping reviews

Top tip 3: Use the JBI Guide to Scoping to conduct your scoping review. To stay up-to-date with emerging methods, join JBI’s Scoping Review Network

Top tip 4: use the PRISMA-ScR for the reporting of your scoping review.

Blog post written by Ciara Keenan and Andrea Tricco

References Arksey, H., & O’Malley, L. (2005). Scoping studies: towards a methodological framework. International journal of social research methodology, 8(1), 19-32.

Munn, Z., Peters, M. D., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E. (2018). Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC medical research methodology, 18(1), 143.

Mays, N., Roberts, E., & Popay, J. (2001). Synthesising research evidence. Studying the organisation and delivery of health services: Research methods, 220.

McGowan, J., Sampson, M., Salzwedel, D. M., Cogo, E., Foerster, V., & Lefebvre, C. (2016). PRESS peer review of electronic search strategies: 2015 guideline statement. Journal of clinical epidemiology, 75, 40-46.

Tricco, A. C., Lillie, E., Zarin, W., O’Brien, K. K., Colquhoun, H., Levac, D., … & Hempel, S. (2018). PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Annals of internal medicine, 169(7), 467-473.

Ciara Keenan
Ciara Keenan
Research Fellow

My research interests include systematic reviews, meta-analyses, race, ethnicity, diversity, homelessness, disability, vulnerable and marginalised groups, post conflict society.