Mapping Review — Evidence and Literature Mapping Review
Evidence and Literature Mapping Review · Also known as: evidence map, systematic map, research map, literature map
A mapping review (also called a systematic map or evidence map) is a form of systematic review that aims to chart the extent, range, and nature of evidence on a broad topic rather than synthesize findings into a single pooled answer. It categorizes studies by key dimensions — such as intervention type, population, outcome, and study design — and presents the resulting landscape visually and tabularly so that researchers and practitioners can identify clusters of evidence, knowledge gaps, and priorities for future primary research or deeper synthesis.
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When to use it
Use a mapping review when a topic is broad or heterogeneous and the primary goal is to describe the existing evidence landscape rather than answer a specific effectiveness question. It is the right choice when you suspect the literature is fragmented across disciplines, when funders need a gap analysis before commissioning trials or systematic reviews, or when a research agenda needs to be set for an emerging field. Do NOT use a mapping review when you need a pooled effect estimate, a best-evidence conclusion, or quality-appraised guidance for practice — in those cases a systematic review with meta-analysis or a scoping review with critical appraisal is more appropriate. Mapping reviews are also unsuitable when the topic is already well-characterized and a targeted review would be more efficient.
Strengths & limitations
- Handles broad, heterogeneous questions that would be too wide for a standard systematic review.
- Explicitly identifies knowledge gaps and research priorities, directly informing research agendas and funding decisions.
- Produces a reusable, updateable evidence database that can be mined for future deeper syntheses.
- Transparent and reproducible: registered protocol, dual screening, and documented search make the process auditable.
- Visual outputs (heat maps, matrices) communicate the evidence landscape efficiently to non-specialist audiences.
- Does not assess the quality or risk of bias of included studies, so cannot support causal or effectiveness conclusions.
- Cannot yield pooled effect estimates or best-evidence summaries — the output is descriptive, not evaluative.
- Comprehensive searching of broad topics is highly resource-intensive in terms of time and reviewer effort.
- The coding framework must be decided a priori; post-hoc changes risk introducing bias.
Frequently asked
How does a mapping review differ from a scoping review?
Both chart the extent of a literature without meta-analytic pooling, but mapping reviews are more structured and produce an explicitly coded, visual evidence database with a heat-map or matrix output focused on identifying gaps. Scoping reviews tend to be broader in purpose — summarizing concepts, types of evidence, and definitions — and may include narrative synthesis of themes. Mapping reviews adhere more strictly to a priori coding frameworks and are typically registered as protocols before searching begins.
Do I need to assess risk of bias in included studies?
No. Critical appraisal of study quality is not a standard component of a mapping review. The goal is to describe the volume and characteristics of the evidence, not evaluate its internal validity. However, study design type is captured as a coding variable, which allows readers to distinguish robust from weaker evidence in the map.
What software is commonly used to build and display evidence maps?
Common tools include EPPI-Mapper, Evidence Map Builder (from the AHRQ), interactive Tableau or Power BI dashboards, and custom Excel-based heat maps. For screening and coding, Rayyan, EPPI-Reviewer, and Covidence are widely used. The choice depends on whether the final map will be static (a table in a report) or interactive and web-published.
How large is a typical mapping review in terms of included studies?
Mapping reviews often include hundreds to several thousands of studies because of their broad scope. Unlike a systematic review with tight inclusion criteria, a mapping review casts a wide net by design. Teams should budget accordingly for screening and coding workload, and consider machine-learning-assisted screening tools for very large record sets.
Should I register a mapping review protocol?
Yes. Protocol registration on PROSPERO (if health-related) or OSF is strongly recommended and increasingly required by journals. Registration demonstrates that the scope, inclusion criteria, and coding framework were defined before searching, protecting against outcome reporting bias and scope drift.
Sources
- James, K. L., Randall, N. P., & Haddaway, N. R. (2016). A methodology for systematic mapping in environmental sciences. Environmental Evidence, 5(1), 7. DOI: 10.1186/s13750-016-0059-6 ↗
- Miake-Lye, I. M., Hempel, S., Shanman, R., & Shekelle, P. G. (2016). What is an evidence map? A systematic review of published evidence maps and their definitions, methods, and products. Systematic Reviews, 5(1), 28. DOI: 10.1186/s13643-016-0204-x ↗
How to cite this page
ScholarGate. (2026, June 3). Evidence and Literature Mapping Review. ScholarGate. https://scholargate.app/en/scientometrics/mapping-review
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
- Bibliometric AnalysisScientometrics↔ compare
- Co-word AnalysisScientometrics↔ compare
- Narrative ReviewScientometrics↔ compare
- Scoping ReviewScientometrics↔ compare
- Systematic Literature ReviewScientometrics↔ compare
- Umbrella ReviewEvidence Synthesis↔ compare