There are MANY types of evidence (or knowledge) synthesis methods. Taking the time to determine which method is most appropriate for your project is critical to successfully undertaking and (most importantly) completing an evidence synthesis project. While most evidence synthesis projects need a systematized approach (detailed and documented plan created prior to the project start for finding and assessing the existing topic literature/data), not all projects require the use of (currently) popular systematic review methodology.
Sutton et al. (2019) offer a comprehensive list of forty-eight evidence synthesis methods from which to choose, grouped into seven families as shown below (the Sutton article is also the basis for the Review Families tree on the Overview tab of this guide).
| Review Family | Included Review Types |
|---|---|
| Traditional Review | Critical review; Integrative review (aka Integrative Synthesis); Narrative review; Narrative summary; State of the Art review |
| Systematic Review | Cochrane Review of Effects; Comparative Effectiveness review; Diagnostic Systematic Review (aka Diagnostic Test Accuracy review); Meta-analysis; Network Meta-analysis; Prognostic review; Psychometric review; Review of Economic Evaluations; Systematic review; Systematic Review of Epidemiology Studies (aka Prevalence and/or Incidence Review Etiology and/or Risk review) |
| Review of Review | Review of Reviews (aka Overview); Umbrella review |
| Rapid Review | Rapid review (aka Rapid Evidence Synthesis); Rapid Evidence Assessment; Rapid Realist Synthesis (aka Rapid Realist Review) |
|
Qualitative Review (aka Experiential Reviews) |
Qualitative Evidence Synthesis; Qualitative Interpretive Meta-synthesis; Qualitative Meta-synthesis; Qualitative Research Synthesis; Best Fit Framework Synthesis; Framework Synthesis; Meta-aggregation; Meta-Ethnography (aka Extended Meta-Ethnography review; Meta-interpretation; Meta-narrative review; Meta-Study (aka Meta-Theory); Meta-Summary; Thematic Synthesis (aka Thematic Analysis) |
| Mixed Methods Review | Mixed Methods Synthesis (aka Mixed Methods review); Bayesian Meta-analysis (aka Bayesian Approach); EPPI-Centre review (aka EPPI-Centre Outcomes plus Views Review); Critical Interpretive Synthesis; Narrative Synthesis (aka Textual Narrative Synthesis); Realist Synthesis (aka Realist review); Rapid Realist Synthesis |
| Purpose-specific Review | Concept Synthesis (aka Concept Analysis or Conceptual Analysis); Content Analysis; Expert Opinion/Policy review; Technology Assessment review (Health Technology Assessment); Scoping review (aka Scoping Study); Mapping review (aka Evidence Map or Systematic Map or Systematic Mapping review); Methodological review (aka Meta-method Methodology Review); Systematic Search and Review; Systematized review |
Selected non-biomedical example articles
The search links below provide (mostly) non-biomedical examples for a small group of evidence synthesis types (evidence maps, systematic reviews, scoping reviews, umbrella reviews). Work will continue to refine these examples, but this is a start.
References:
The Right Review website offers two options:
OR
Most of the methods are accompanied by very useful conduct and reporting guideline information (or see the Methodological and Reporting guidance modules on this page), as well as example articles using that methodology.
Many people equate evidence synthesis with systematic reviews. While systematic reviews are not the only type of evidence synthesis, they are currently very popular. Systematic reviews, specifically:
Systematic reviews (with our without meta-analysis) are characterized as at/near the pinnacle of the evidence triangle (the purple stripe near the top of the image below) identifying their importance in evaluating and distilling existing research.
However, a systematic review will not be appropriate for every project. If the goal is not to answer a specific question but instead to understand or explore the literature, consider a scoping or mapping review or even a traditional narrative review, all of which still require systematized approaches to the project (see the "Evidence synthesis methods" module above).
Credit: "About Cochrane Reviews" https://www.cochranelibrary.com/about/about-cochrane-reviews (no date)
Research design and evidence, by CFCF, CC BY-SA 4.0, via Wikimedia Commons
Methodological guidance, often found in the form of handbooks or manuals, describe how to conduct the review. These handbooks and guides are developed by teams of experienced researchers and synthesizers.
To conduct a proper systematic review and/or meta-analysis, you'll need to follow accepted methodological guidance. Much of the guidance currently available is rooted in health and medicine, but there are existing adaptations for social, animal/food, and environmental sciences. As evidence synthesis expands to other fields, formal guidance for other disciplines will continue to be developed. If you can't find guidance specific to your field, use a handbook or manual that is most applicable.
Note that this library guide is not methodological guidance - rather, we have curated resources to help you through the process, and linked to methodological guidance (and other helpful material) throughout.
Animal/Food
Environment
Healthcare
Social Sciences
These publications are not full manuals or handbooks, but can supplement the guidance above. This material is especially useful if there is not yet formal guidance available in your discipline or field.
Engineering Education
Computer Science
Social Research
Software Engineering
Credit: "Methodological Guidance" (Virginia Tech University Libraries) adapted by OSU Libraries & Press under CC BY-NC-SA 4.0.
Even though reporting is often thought of as one of the last phases of research, it is best to choose and become familiar with reporting guidelines early. This makes the reporting process easier, as you will already know and have thoroughly documented everything you need to report in the final manuscript (or other output). For proper reporting of a systematic review and/or meta-analysis, you must follow a reporting guideline.
Credit: "Reporting Guidelines" (Virginia Tech University Libraries) adapted by OSU Libraries & Press under CC BY-NC-SA 4.0
