Boxer Library
Evidence synthesis is the process by which a researcher collects relevant information in order to answer a research question. This practice is the backbone of many types of review-based research and is essential to the understanding of evidence-based practice. Evidence synthesis projects allow researchers to combine multiple studies on the same topic to draw larger conclusions. By gathering more evidence on a topic, researchers can be more confident in their conclusions regarding treatments, procedures, and other clinical decisions.
Two important evidence synthesis organizations are the Joanna Briggs Institute (JBI) and Cochrane. The RFUMS Center for Interprofessional Evidence-Based Practice is an affiliate of JBI.
There are many different types of evidence synthesis projects and it is important to determine which one is right for your research goals. One helpful tool is Right Review. You can also see a chart of different review types below.
| Review Type | Description | Search | Appraisal | Synthesis | Analysis | Time Needed | Team Needed? |
| Literature Review | Generic term: published materials that provide examination of recent or current literature. Can cover wide range of subjects at various levels of completeness and comprehensiveness. May include research findings. | May or may not include comprehensive searching | May or may not include quality assessment | Typically narrative | Analysis may be chronological, conceptual, thematic, etc. | Weeks to Months | No, can complete individually |
| Meta-Analysis | Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results | Aims for exhaustive, comprehensive searching. May use funnel plot to assess completeness | Quality assessment may determine inclusion/exclusion and/or sensitivity analyses | Graphical and tabular with narrative commentary | Numerical analysis of measures of effect assuming absence of heterogeneity | At least a year | Yes |
| Scoping Review | Preliminary assessment of potential size and scope of available research literature. Aims to identify nature and extent of research evidence (usually including ongoing research) | Completeness of searching determined by time/scope constraints. May include research in progress. | No formal quality assessment | Typically tabular with some narrative commentary | Characterizes quantity and quality of literature, perhaps by study design and other key features. Attempts to specify a viable review | A least a year | Yes |
| Systematic Review | Seeks to systematically search for, appraise and synthesize research evidence, often adhering to guidelines on the conduct of a review | Aims for exhaustive, comprehensive searching | Quality assessment may determine inclusion/exclusion criteria | Typically narrative with a tabular accompaniment | What is known; recommendations for practice. What remains unknown; uncertainty around findings, recommendations for future research | On average 18 months; at LEAST a year | Yes |
CHART REPRODUCED AND ADOPTED FROM: GRANT MJ, BOOTH A. A TYPOLOGY OF REVIEWS: AN ANALYSIS OF 14 REVIEW TYPES AND ASSOCIATED METHODOLOGIES. HEALTH INFO LIBR J. 2009 JUN;26(2):91-108. DOI: 10.1111/J.1471-1842.2009.00848.X. REVIEW. PUBMED PMID: 19490148.
