There are various different types of structured reviews of published research. Systematic reviews and meta-analyses of research evidence are well established and well known types of studies. Scoping reviews and rapid review are two types of studies which emerged in the healthcare literature from 2010 and are now a recognized method of identifying and surveying issues on both broad topics and specific clinical questions.
Scoping reviews are frequently undertaken to determine the feasibility of more specific research questions. The purpose of scoping reviews has been presented as follows:
A systematic review might typically focus on a well-defined question where appropriate study designs can be identified in advance; a scoping study might discuss broader topics where many different study designs might be applicable. A scoping study is less likely to seek to address specific research questions in detail and will not usually assess all aspects of the quality of data or evidence.
Approaches to scoping reviews
The steps in conducting a scoping study are similar to many review types while maintaining broad and general perspectives:
Scoping reviews are not necessarily quick or rapid alternatives to systematic reviews. In certain cases, as in BEME (Best Evidence Medical Education) reviews for instance, a scoping evaluation is a required preliminary to the main study. Other factors to consider include:
To find examples of published scoping reviews in Medline simply search “scoping review” and combine with any topic of your choice.
Resources to consult on scoping reviews.
Arksey H. and O'Malley L. Scoping Studies: towards a methodological framework. International Journal of Social Research Methodology, 2005;8(1):19-32. https://doi.org/10.1080/1364557032000119616
Colquhoun HL, Levac D, O'Brien KK et al Scoping reviews: time for clarity in definition, methods, and reporting. J Clin Epidemiol. 2014 Dec;67(12):1291-4. https://doi.org/10.1016/j.jclinepi.2014.03.013
Peters MDJ, Godfrey C, McInerney P, Baldini Soares C, Khalil H, Parker D. Chapter 11: Scoping Reviews. In: Aromataris E, Munn Z (Editors). Joanna Briggs Institute Reviewer's Manual. The Joanna Briggs Institute, 2017. Available from https://reviewersmanual.joannabriggs.org/
Munn Z, Peters M, Stern C, et al. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Medical Research Methodology. 2018;18:143. Available from: https://doi.org/10.1186/s12874-018-0611-x
Peters M, Godfrey C, Khalil H, et al. Guidance for Conducting Systematic Scoping Reviews. Int J Evid Based Healthc. 2015;13:141-146. https://doi.org/10.1097/XEB.0000000000000050
Tricco AC, Lillie E, Zarin W, et al . PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. Ann Intern Med. 2018. https://doi.org/10.7326/M18-0850
[1] Arksey, H., & O’Malley, L. (2005). Scoping studies: Towards a methodological framework. International Journal of Social Research Methodology: Theory & Practice, 8(1), 19-32. Available from: http://eprints.whiterose.ac.uk/1618/1/Scopingstudies.pdf
Mapping reviews are focused on a visual synthesis of the data and are question based rather than topic based like the scoping review.
Mapping reviews are best designed for:
Examples:
Meta-analysis is the use of statistical methods to summarise the results of independent studies. By combining information from all relevant studies, meta-analyses can provide more precise estimates of the effects of health care than those derived from the individual studies included within a review. Meta-analyses also facilitate investigations of the consistency of evidence across studies, and the exploration of differences across studies (Cochrane Handbook, 1.2.2). More information on meta-analyses can be found in Cochrane Handbook, Chapter 9.
“Rapid reviews are a form of evidence synthesis that may provide more timely information for decision making compared with standard systematic reviews. Systematic reviews are defined as “a review of a clearly formulated question(s) that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review.”[1]
“Rapid reviews are literature reviews that use methods to accelerate or streamline traditional systematic review processes in order to meet the needs and timelines of the end-users (e.g., government policymakers, health care institutions, health professionals, and patient associations) .”[2]
Rapid reviews target high quality and authoritative resources for time-critical decision-making or clinically urgent questions. Like a systematic reviews they aim to identify the key concepts, theories and resources in a field, and to survey the major research studies. Less time may be spent on critical appraisal as systematic reviews, evidence briefs and clinical guidelines are sought in preference to exhaustive coverage of primary studies. The objective is to apply systematic levels of search and appraisal but within shorter timeframes.
The methods of conducting rapid reviews varies widely, and are typically done in less than 5 weeks. Often policy makers require a short deadline and a systematic review for synthesizing the evidence is not practical. A rapid review speeds up the systematic review process by omitting stages of the systematic review making it less rigorous.
Rapid reviews are best designed for: broader PICO questions, new or emerging research topics, updates of previous reviews, critical topics or to assess what is already known about a policy.
The World Health Organization presents a wide ranging overview in the following guide:
To find examples of published rapid reviews search in Medline search “rapid review” and any subject term -eg- “women’s health”
Resources to consult on rapid reviews
[1] Higgins JP, Green S. Cochrane handbook for systematic reviews of interventions Version 5.1. 0. Cochrane Collaboration; 2012. [updated March 2011] Cochrane Collaboration. Available from: https://handbook-5-1.cochrane.org/
[2] Ganann R, Ciliska D, Thomas H. Expediting systematic reviews: methods and implications of rapid reviews. Implementation Science. 2010; 5(1):56. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2914085/
An Umbrella review is a synthesis of existing reviews, only including the highest level of evidence such as systematic reviews and meta-analyes. It specifically refers to review compiling evidence from multiple reviews into one accessible and usable document. Umbrella reviews focuses on broad condition or problem for which there are competing interventions and highlights reviews that address these interventions and their result.
Methodology paper: Aromataris, E, Fernandez, R, Godfrey, CM, Holly, C, Khalil, H & Tungpunkom, P 2015, 'Summarizing systematic reviews: Methodological development, conduct and reporting of an umbrella review approach', Int J Evid Based Healthc, vol. 13, no. 3, pp. 132-140.
"Mixed-methods systematic reviews can be defined as combining the findings of qualitative and quantitative studies within a single systematic review to address the same overlapping or complementary review questions." (Harden A. 2010)
Mixed Methods Reviews are best designed for:
Harden A. Mixed-Methods Systematic Reviews: Integrating quantitative and qualitative findings. NCDDR:FOCUS. 2010.