Literature reviews are comprehensive summaries and syntheses of the previous research on a given topic. While narrative reviews (UpToDate or Natural Medicines) are common across all academic disciplines, reviews that focus on appraising and synthesizing research evidence are increasingly important in the health and social sciences.
Most evidence synthesis methods use formal and explicit methods to identify, select and combine results from multiple studies, making evidence synthesis a form of meta-research.
The review purpose, methods used, and the results produced vary among different kinds of literature reviews; some of the common types of literature review are detailed below.
Common Types of Literature Reviews
Narrative (Literature) Review: Topic Background Information [UpToDate]
- A broad term referring to reviews with a wide scope and non-standardized methodology
- Search strategies, comprehensiveness of literature search, time range covered, and method of synthesis will vary and do not follow an established protocol.
Integrative Review [ERIC]
- A type of literature review based on a systematic, structured literature search
- Often has a broadly defined purpose or review question
- Seeks to generate or refine and theory or hypothesis and/or develop a holistic understanding of a topic of interest
- Relies on diverse sources of data (e.g. empirical, theoretical or methodological literature, qualitative or quantitative studies)
PubMed@SMU, Cochrane Library, Ovid, Trip Database Pro.
- Systematically and transparently collects and categorize existing evidence on a question of scientific, policy or management importance
- Follows a research protocol that is established a priori
- Compares, evaluates, and synthesizes evidence, often in a search for the effect of an intervention or exposure
- Some sub-types of systematic reviews include SRs of intervention effectiveness, diagnosis, prognosis, etiology, qualitative evidence, economic evidence, and more.
- Time-intensive and often takes months to a year or more to complete
- The most commonly referred to type of evidence synthesis; sometimes confused as a blanket term for other types of reviews
- Statistical technique for combining the findings from disparate quantitative studies
- Uses statistical methods to objectively evaluate, synthesize, and summarize results
- Often conducted as part of a systematic review
- Systematically and transparently collects and categorizes existing evidence on a broad question of scientific, policy or management importance
- Seeks to identify research gaps, identify key concepts and characteristics of the literature and/or examine how research is conducted on a topic of interest
- Follows a research protocol that is established a priori
- Useful when the complexity or heterogeneity of the body of literature does not lend itself to a precise systematic review
- Useful if authors do not have a single, precise review question
- May critically evaluate existing evidence, but does not attempt to synthesize the results in the way a systematic review would
- May take longer than a systematic review
- Applies a systematic review methodology within a time-constrained setting
- Follows a research protocol that is established a priori
- Employs methodological "shortcuts" (e.g., limiting search terms and the scope of the literature search), at the risk of introducing bias
- Useful for addressing issues requiring quick decisions, such as developing policy recommendations
- Reviews other systematic reviews on a topic
- Often defines a broader question than is typical of a traditional systematic review
- Most useful when there are competing interventions to consider
- Follows a research protocol that is established a priori
