Evidence synthesis refers to the structured, transparent process of gathering, evaluating, and combining findings from multiple research studies to answer a specific question.

Rather than relying on a single study, evidence synthesis methods (such as systematic reviews, meta-analyses, and scoping reviews) bring together all available, high-quality research on a topic to identify overall patterns, strengths, and gaps in the evidence base.

It is a cornerstone of evidence-based practice (EBP)—helping clinicians, educators, and policy makers make decisions informed by the totality of existing research rather than isolated findings.

Grant, M. J., & Booth, A. (2009). A typology of reviews: An analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108.  https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1471-1842.2009.00848.x

Cornell University Library Review Decision Tree

Text

What review is right for you

• Clearly defined question (often PICO)

• Pre-registered protocol (PROSPERO, OSF)

• Two-person screening and data extraction

• Transparent inclusion/exclusion criteria

• Comprehensive search in multiple databases

• PRISMA flow diagram

• Critical appraisal and synthesis

Typical Team Composition

PI, co-investigators, methodologist, subject experts, statistician, librarians.

A concise playbook for systematic reviews: define eligibility, screen studies, and extract data.

List of reporting items for researchers to use when documenting study details in IMRAD (Intro, Methods, Results, & Discussion) and beyond (abstracts, appendix, supplemental).

Conducting & Reporting Guidelines Examples

• Methodological Expectations of Cochrane Intervention Reviews (MECIR)

Standards for the conduct and reporting of new Cochrane Intervention Reviews

• Campbell Standards for Conduct and Reporting of Systematic Reviews

Standards for the conduct and reporting of Campbell systematic reviews

PRISMA checklist + flow diagram

PRISMA, PRISMA-S, and PRISMA-P  What’s the difference?

• A blueprint for your entire project

• States your rationale, hypothesis, and planned methodology  

• Created a priori ensures decision are made objectively

• Registered/shared for transparency

How much detail do I need?

• PRISMA-P - Preferred Reporting Items for Systematic Reviews & Meta-analysis - for Protocols (https://www.prisma-statement.org/protocols)

• Chapter 5 (Protocols) in Campbell Systematic Reviews: Policies & guidelines 

• Guidance for scoping reviews: Peters et al., (2022). Best practice guidance and reporting items for the development of scoping review protocols. JBI Evidence Synthesis, 20(4), 953-968. https://doi.org/10.11124/jbies-21-00242 

Protocol Registries for Evidence Syntheses with Health Related Outcomes

PROSPERO

COCHRANE

 

Inappropriate or inadequate search strategies may fail to identify records that are included in bibliographic databases.  

     

Research Strategy & Planning

 Evidence synthesis requires not only top notch search results, but reproducibility.

• Platform capabilities: Which databases or interfaces are you using (e.g., PubMed, CINAHL, Medline via EBSCO or ProQuest)?
• Saving searches & histories: Does the platform allow saving, rerunning, and exporting your search strategies for PRISMA-S documentation?
• Reproducibility: Can another researcher repeat your search exactly (same filters, syntax, date limits)?
• Working with results: Are there tools for citation management, tagging, or exporting to Covidence/Rayyan/Zotero?
• Downloading results: How many results can you export at once? (some limit to 200–500 per batch)

Document everything - decisions, what worked, what didn’t.

Research Strategy & Planning

 Search strategies need to be customized for each database 

Document everything - decisions, what worked, what didn’t.

• Not all criteria need to be included in the search strategy and are better incorporated during screening process

• This may vary between databases

• Think about the concepts that are likely to appear in titles/abstracts vs. full text

• Finding a balance between too narrow (few) and too broad (many)

Gold standard’ or Seed articles,

Document everything - decisions, what worked, what didn’t.

For databases with a good thesaurus, look up these articles and explore the assigned subject headings.

• Screen all studies retrieved from the search against eligibility criteria

• Perform risk of bias assessment for included studies 

Melbourne Library

Article Screening Software: Tools & Library Support

• We don’t license Covidence or DistillerSR.

•  Use free options via the SR Toolbox       (tool directory by review stage).
• Practical stack we support: Zotero, Excel/Sheets.
• We can help handle deduplication and PDF harvesting/organizing.

• We don’t license Covidence or DistillerSR.

Bias Assessment Tools

• Mayo Clinic's Critical Appraisal by Study Design

• CASP Checklists

• LATITUDES Network

• Consider the populations that your research team works with and how research quality may be defined differently in different knowledge systems

• Risk of Bias and Critical appraisal tools must be designed and fit for purpose

etorres@hpu.edu 

library@hpu.edu