Evidence syntheses, also knows simply as 'reviews', are a form of publication that summarizes or analyses the research results of other publications. There are many different types of evidence synthesis that may vary by their purpose or goal as well as other characteristics. Some merely provide an easier to understand summary of previous work, others critically analyse the strength of published studies, explore the existing literature to identify research gaps, or pool the results of previous studies using statistical methods to estimate the overall strength of evidence for an outcome.
Although all may be referred to as 'reviews', they may differ by:
This guide has tools to help you identify the type of evidence synthesis or review is best for your research goals and limitations.
| Type of Review | Also called / Variants | Goal of Review | # of People | Time to Complete | Type(s) of publications Included | Key Features |
|---|---|---|---|---|---|---|
| Narrative Review | Review Article, Literature Review | Describe the published literature in narrative form. | 1 or more | 1 month+ | Determined by author. | No set methodology, non-exhaustive search, no evidence appraisal. |
| Rapid Review | To quickly appraise published research to answer a urgent need for evidence to inform clinical practice or policy in a time-sensitive manner for a specific question. . | > 3 | ~ 6 months | Often only Published literature or specific study designs (e.g. Randomized Controlled Trials) | Systematic review methods are 'streamlined' to reduce time spent screening, etc. | |
| Scoping Review | Mapping Review | Map out the body of literature relating to my topic to identify themes and gaps in the literature | > 3 | > 6 months | Published literature | Analyze themes, gaps, study designs or other characteristics. No evaluation of quality of evidence. |
| Umbrella Review | Review of Reviews | Compare and integrate the results of existing evidence synthesis reviews to answer a research question | > 3 | > 6 months | Other evidence synthesis reviews | Only existing evidence syntheses are used, often to gather evidence on multiple interventions. |
| Integrative Review | To gain new insight on the research question by integrating different perspectives across disciplines. | > 3 | > 6 months | Can include both empirical (quantitative) studies and theoretical (qualitative) literature. | ||
| Systematic Review | Systematically locate, appraise, and synthesize all published and unpublished research evidence relating to a specific research question. | > 3 | > 6 months | Primary studies, including published, unpublished, and 'grey' literature (dissertations, conference abstracts, etc.) | Methods & inclusion criteria determined before main search. Multiple independent screeners and data extractors. Grading of evidence and Risk of Bias. May or may not include a meta analyses depending on the type of data available. | |
| Meta Analysis | Network Meta Analysis (comparison of multiple interventions) | Use advanced statistical methods to pool and synthesize data from multiple studies, in order to come to a more statistically reliable result for the research question. | > 3 | > 6 months | Primary studies, quantitative | All aspects of Systematic Review, plus statistical pooling of data across studies. |
The Mulford Health Science Librarians' service model for assisting with evidence syntheses is one focused on consultation and guidance on the search strategies to uncover existing evidence.
For most types of evidence syntheses including narrative, umbrella, integrative, scoping, and rapid reviews, the librarians can:
For full systematic reviews and/or meta-analyses, the consultation requires more in-depth preparation by our librarians, so we require an intake form before a consultation can be scheduled with details about your proposed review. See the Systematic Reviews page of this guide for details. Additionally, in this case, we cannot work with students unless they join a consultation with the faculty, resident physical, or fellow who is leading the systematic review team.