Evidence Synthesis Reviews

What is Evidence Synthesis?

"Evidence synthesis uses formal, explicit, and rigorous methods to bring together the findings of research already completed, to provide an account of the totality what is known from that pre-existing research," (Evidence Synthesis International, 2019).

Evidence Synthesis Reviews are literature review methodologies that are designed to examine all relevant evidence (studies and literature) in response to a well-formulated research question.

Evidence Synthesis Reviews are rooted in evidence based medicine/practice most notably in the Health Sciences, but has been increasingly used in other disciplines, including Public Health, Education, Sciences (i.e. Ecological, Environmental, and Agricultural Science, Engineering, Computer Science), Business and Management, and Social Sciences (i.e. Social Work, Criminal Justice, Linguistics).

Evidence Synthesis Reviews are used to inform evidence based practice, decision making, and policy development across disciplines.

Evidence Synthesis International. (2019, October 1). About evidence synthesis. Evidence Synthesis International. https://evidencesynthesis.org/about/about-evidence-synthesis/

How is Evidence Synthesis Different from a Literature (Narrative) Review?

Evidence synthesis reviews intend to systematically search, collect, and analyze all available literature responding to a well-formulated research question under carefully defined parameters.

Evidence synthesis reviews are designed to make research open, accessible, and transparent. Every step of the process is documented in a protocol that should be registered before conducting the study. Registering an evidence synthesis review protocol aims to ensure transparency, reproducibility, and replicability of the research. By registering the protocol and synthesizing all published and unpublished literature, evidence synthesis are also designed to minimize bias and questionable research practices, such as:

• p-Hacking (aka inflation bias, selective reporting, data dredging)
• HARKing (Hypothesizing After Results are Known)
• Underpowered studies
• Bias against the null hypothesis

Why Conduct an Evidence Synthesis Review?

1.  To examine all scholarship (published and unpublished) in response to a given question
2.  To understand the state of research on a particular intervention, practice, program, policy, process, material, etc
3.  To identify gaps in the literature on a specific topic

Considerations for Conducting an Evidence Synthesis Review

1. Is your research question compatible with an evidence synthesis review?
2. Do you have a research team of 3 or more people?
3. Are you able to commit to 12+ months to conducting the review?*
4. Do you intend to publish the review and have identified submission criteria for evidence synthesis reviews for a particular publication?

*Scoping reviews may take less than 12 months