Faculty Research Resources: Systematic Review & Evidence Synthesis

Evidence synthesis is any type of research methodology where researchers identify, select, and combine results from multiple studies.

This area of research is used to identify gaps in the evidence and establish a base for evidence-based decision-making.

Few common types of evidence synthesis are:

• Systematic review
• Literature (narrative) review
• Scoping review
• Rapid review
• Meta-analysis

Systematic reviews collect identify, appraise, and synthesize all available evidence to answer a well-formulated research question using explicit, reproducible methodology.

Key characteristics include: 

• a systematic search in relevant subject databases
• results independently screened according to pre-defined inclusion and exclusion criteria
• critical appraisal of selected research studies
• thorough presentation of the characteristics and findings of the included studies

Librarians offer various levels of assistance with evidence synthesis. Refer to the library's policy for more information:

Cochrane, Scottish Intercollegiate Guidelines Network (SIGN), and Joanna Briggs Institute (JBI) are organizations that support evidence-based health decisions with evidence synthesis resources.

It is best practice to register a systematic review with PROSPERO or another registry like Open Science Framework (OSF). 

Systematic review searches are distinctive in their comprehensiveness.  Studies show that consulting with a librarian improve the quality of systematic review searches.

Librarians can advise on the most appropriate search strategies and databases.

Common systematic review databases include:

Grey literature includes conference papers, dissertations, theses, trial registers, and is not controlled by commercial publishing. 

A few repositories of grey literature are:

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Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 

Covidence is a web-based software for screening and data extraction provided by Midwestern University Libraries. 

Rayyan is an alternative to Covidence. It is a free online tool aiding in the screening and coding of studies for systematic reviews.

EndNote 21 is a reference management software that facilitates documenting record retrieval. 

Evaluate studies for quality using assessment tools such as the Modified Downs & Black Checklist. Other examples of critical appraisal tools include: 

1. Boland A, Cherry MG, Dickson R. Doing a systematic review: a student's guide. 2nd ed. SAGE; 2017.
2. Foster M J, Jewell S T. Assembling the pieces of a systematic review: guide for librarians. Rowman & Littlefield; 2017.
3. Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009;26(2):91-108. doi:10.1111/j.1471-1842.2009.00848.x
4. Haile ZT. Critical Appraisal Tools and Reporting Guidelines. J Hum Lact. 2022;38(1):21-27. doi:10.1177/08903344211058374
5. Mak S, Thomas A. An Introduction to Scoping Reviews. J Grad Med Educ. 2022;14(5):561-564. doi:10.4300/JGME-D-22-00620.1
6. PLoS Medicine Editors. Best practice in systematic reviews: the importance of protocols and registration. PLoS Med. 2011;8(2):e1001009. doi:10.1371/journal.pmed.1001009
7. Stellrecht E, Samuel A, Maggio LA. A reader’s guide to medical education systematic reviews. J Grad Méd Educ. 2022;14(2):176-177. doi:10.4300/jgme-d-22-00114.1