The following is a list of the most common Advanced Reviews. Evidence Synthesis methods are evolving rapidly, especially those handling qualitative data. New methods are in the process of developing, some are merging, and others are known by different names in different disciplines. Here we focus on the most common and combine various qualitative and mixed methods reviews into the umbrella term Qualitative Evidence Syntheses.
Systematic reviews are a rigorous and scientifically sound type of literature review that uses explicit, transparent, and replicable methods and techniques through all stages to minimize bias in the collection, screening, appraisal, synthesis, and reporting of evidence to address a pre-specified research question. Systematic reviews include a protocol developed and often registered in advance that guides the process. These reviews must have
Guidelines for conducting Systematic Reviews
Standards for reporting Systematic Reviews
“Scoping reviews are a type of evidence synthesis that aim to systematically identify and map the breadth of evidence available on a particular topic, field, concept, or issue, often irrespective of source (ie, primary research, reviews, non-empirical evidence) within or across particular contexts. Scoping reviews can clarify key concepts/definitions in the literature and identify key characteristics or factors related to a concept, including those related to methodological research” (Munn et al., 2022).
Guidelines for conducting Scoping Reviews
Standards for reporting Scoping Reviews
Qualitative evidence syntheses (QES) may solely involve qualitative data, or it may include mixed methods (Noyes et al., 2018). They may involve a single synthesis method or combine multiple synthesis methods. These methods require more iteration throughout the process than a systematic review due to the variety of qualitative research methods that may be synthesized. Quality appraisal and the risk of bias of qualitative studies, especially across different qualitative research methods, can be problematic and may or may not be included. Researchers will need to consider whether they intend to conduct deductive analysis, assigning data to preexisting categories, or inductive analysis, developing new categories based on the data. Deductive approaches benefit from pre-developed extraction and coding templates, whereas inductive approaches require iteration as data are analyzed. In practice, this review type typically uses the name of the synthesis methods employed rather than the name of the framework, though they may also be called qualitative systematic reviews.
Guidelines for conducting qualitative evidence syntheses
Standards for reporting qualitative evidence syntheses
The trending view is that rapid reviews do not qualify as a separate review framework but are more appropriately categorized as an approach to a systematic review (Tricco et al., 2022). Rapid reviews involve all the same stages as a systematic review but are truncated based on available time and resource restrictions. These reviews do not replace systematic reviews because their conclusions are more subject to potential biases and methodological flaws, but they do play an important role in providing solutions during rapidly developing phenomena, such as the COVID-19 pandemic. General consensus determines that methods should be completed as thoroughly and rigorously as possible within the project team’s constraints and should be transparently communicated.
Another approach to systematic reviews is the living systematic review (LSR). This approach was developed to deal with the issue of keeping the best evidence up to date for decision makers. In LSRs, researchers incorporate new studies as they become available. This is a decision made prior to conducting the review and incorporated into the protocol (Elliott et al., 2017). The framework used for an LSR is the same as for a systematic review. The only difference is how and when they are updated. The frequency and method for updating are determined in the protocol, with researchers committing to rerunning the search and updating results at regular intervals, usually between 1 and 6 months. Due to the intensity and longterm commitment of LSRs, they are typically used only for research questions with immediate, continuous, and critical impact on practice or policy.
Introduction to Evidence Synthesis Methodologies: Systematic, Scoping, Rapid, and Systematized Reviews, What's the difference?
This video is a recording of a workshop given for researchers at the University of Nebraska-Lincoln on February 6, 2024 by the Research Partnerships department of UNL Libraries. To learn more about us and upcoming workshops, visit https://unl.libguides.com/RP.
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Higgins, J. P. T., Thomas, J., Chandler, J., Cumpston, M., Li, T., Page, M. J., & Welch, V. A. (Eds.). (2024). Cochrane handbook for systematic reviews of interventions (6.5). Wiley. https://doi.org/10.1002/9781119536604
Krnic Martinic, M., Pieper, D., Glatt, A., & Puljak, L. (2019). Definition of a systematic review used in overviews of systematic reviews, meta-epidemiological studies and textbooks. BMC Medical Research Methodology, 19(1), 203. https://doi.org/ 10.1186/s12874-019-0855-0
Munn, Z., Pollock, D., Khalil, H., Alexander, L., Mclnerney, P., Godfrey, C. M., Peters, M., & Tricco, A. C. (2022). What are scoping reviews? Providing a formal definition of scoping reviews as a type of evidence synthesis. JBI Evidence Synthesis, 20(4), 950–952. https://doi.org/10.11124/JBIES-21-00483
Noyes, J., Booth, A., Cargo, M., Flemming, K., Garside, R., Hannes, K., Harden, A., Harris, J., Lewin, S., Pantoja, T., & Thomas, J. (2018). Cochrane Qualitative and Implementation Methods Group guidance series: 1. Introduction. Journal of Clinical Epidemiology, 97, 35–38. https://doi.org/10.1016/j.jclinepi.2017.09.025
Tricco, A. C., Khalil, H., Holly, C., Feyissa, G., Godfrey, C., Evans, C., Sawchuck, D., Sudhakar, M., Asahngwa, C., Stannard, D., Abdulahi, M., Bonnano, L., Aromataris, E., McInerney, P., Wilson, R., Pang, D., Wang, Z., Cardoso, A. F., Peters, M. D. J., . . . & Munn, Z. (2022). Rapid reviews and the methodological rigor of evidence synthesis: A JBI position statement. JBI Evidence Synthesis, 20(4), 944–949. https://doi.org/10.11124/JBIES-21-00371