Note: The majority of this blog post is distilled from information presented at the IMLS-funded Evidence Synthesis Institute created by librarians in partnership from the University of Minnesota, Cornell University and Carnegie Mellon University; which the author attended in the spring of 2021 and highly recommends. For more information, see: University of Minnesota Libraries, Evidence of Synthesis Institute.

Evidence synthesis “refers to any method of identifying, selecting, and combining results from multiple studies” (Cornell, 2021). Literature reviews, which discuss the published literature on a topic, and systematic reviews, which use explicit methods to collate and analyze primary literature, are probably the most well-known type of evidence synthesis; however, the practice encompasses a number of other review types as well, such as:

• Meta-Analysis – statistically combines results from quantitative studies. Studies must feature the same characteristic(s) being measured in the same way. 
• Scoping Review – collects and categorizes evidence in order to identify gaps in knowledge.
• Rapid Review – utilizes systematic review methodology with shortcuts in order to address a topic in a shorter amount of time.
• Umbrella Review – reviews published systematic reviews, often to address a broader topic.

For an in-depth discussion of different review types, including many more not listed here, see Grant (2009).

Evidence synthesis is well established in the medical field, with systematic reviews in particular being an important part of the medical literature. These reviews investigate treatments, interventions, and other aspects of medicine, and are used to inform standards of care. The Cochrane Library is one well-known source of high-quality systematic reviews and meta-analyses in healthcare. Evidence synthesis is increasingly relevant in other disciplines as well, with different organizations working to advance this type of research in their respective fields. For example, the Campbell Collaboration provides resources for reviews in education and social sciences, while the Center for Evidence-Based Management focuses on reviews in business. The Centre for Evidence-Based Agriculture works to further evidence synthesis in agri-food research. Meanwhile, the Collaboration for Environmental Evidence promotes evidence synthesis in environmental science and policy and publishes reviews in their journal, Environmental Evidence.

Librarians lend valuable skills to the evidence synthesis process, and awareness of the importance of including librarians in evidence synthesis research teams is growing. A research team should ideally include researchers in the discipline, a statistician (if quantitative data will be investigated), and a librarian to work with the team to plan an effective search strategy, including keywords and which databases to search. Librarians’ involvement can range from consultants to full co-authors. Best practice in evidence synthesis also includes completion of a protocol for the review. The protocol includes the research question, search strategy, databases to be searched, inclusion and exclusion criteria for articles, a sample of relevant articles already identified, and other information. Publication of the protocol allows for reproducibility, transparency and sharing of knowledge which advances the practice of evidence synthesis. A template for evidence synthesis protocols created by librarians Kate Ghezzi-Kopel and Jaron Porciello (2020) can be found on the Open Science Framework.

An increasing number of academic libraries are providing services in evidence synthesis. A wealth of information is available online courtesy of libraries with well-established programs, such as Cornell University Library. Their website features a comprehensive guide to evidence synthesis and their corresponding service for researchers. The University of Minnesota Libraries is another excellent example. Information about their Systematic Review and Evidence Synthesis Service, including a request form to gather preliminary information from interested researchers.

Staffing levels, time commitments and areas of expertise are all factors that need to be considered in starting an evidence synthesis service. The first step for librarians interested in evidence synthesis is to complete in-depth training. A number of organizations fill this need. One excellent option is the Evidence Synthesis Institute, which is funded by the IMLS and provided by the University of Minnesota, Cornell University and Carnegie Mellon University. The Institute provides training on evidence synthesis specifically geared toward librarians supporting disciplines outside of the health sciences. For more information, see  University of Minnesota Libraries, Evidence Synthesis Institute.

Kimberly Reycraft, Florida Gulf Coast University

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