Types of Literature Reviews and Their Uses
Literature review types are distinguished by research purpose, question scope, evidence source and methodological structure. Narrative, systematic, scoping, integrative, rapid, umbrella, critical and systematised reviews fit different combinations of those attributes, so the appropriate family depends on what the research question must accomplish, the evidence available and the methodological constraints rather than on one universally best review type.
Match the review family to the research task
Start with the main job the review needs to perform, then check the deciding methodological cue. These are orientation points, not fixed rules across every discipline.
Interpret a broad body of literature
Narrative review fits broad contextual or thematic synthesis. If the central task is argument-led evaluation of assumptions, tensions or conceptual weaknesses, examine a critical review instead.
Map a broad or heterogeneous evidence field
Scoping review fits questions about the extent, characteristics, concepts or gaps in the evidence base.
Answer a focused question with explicit methods
Systematic review fits predefined, transparent searching, selection, appraisal and synthesis. Under genuine time or resource constraints, a rapid review may streamline selected methods and must report those modifications.
Integrate different forms of evidence
Integrative review brings diverse empirical and theoretical literature together when the research purpose requires an integrated interpretation.
Synthesize existing reviews
Umbrella review uses review-level evidence when multiple relevant systematic reviews already exist and overlap and review quality can be assessed.
Use selected systematic elements under project constraints
Systematised review can retain structured searching, explicit criteria or documented selection without claiming that every requirement of a full systematic review has been met.
Decision boundary: the review label alone is not enough. Discipline, assignment requirements, evidence maturity, time, resources and the methods actually reported can change which approach is suitable.
Literature review classifications vary across disciplines, and terminology and boundaries between review families can overlap.
UCLA Library describes its review typology as neither definitive nor comprehensive and presents it within a health-sciences context.
The University Health Network similarly uses literature review as a broad term covering review types that can differ in their completeness and comprehensiveness, so classifications should be interpreted within the relevant disciplinary and methodological context.
The main dimensions distinguishing review families include their purpose, scope, evidence base, methodology, and intended form of synthesis.
A review type is not automatically the same as a synthesis technique; for example, UCLA Library describes meta-analysis as a technique for statistically combining quantitative study results.
These dimensions provide the basis for understanding the major literature review types and the contexts in which they are used.
Table of Contents
Major Literature Review Types
Major literature review types differ primarily in their purpose, scope, evidence source, methodological structure, and synthesis intent.
A narrative review provides a flexible synthesis of literature around a topic, while a systematic review uses explicit methods to address a focused research question and a scoping review systematically maps a broader evidence field.
Integrative, rapid, umbrella, critical, and systematised reviews represent other combinations of these shared attributes and serve different research purposes.
The diagram groups the approved review families under the broader literature-review concept while showing their separation by purpose and scope.
The table compares each review type through the same high-level attributes: primary purpose, typical scope, and methodological cue.
This common frame makes the differences between review families scannable without turning the comparison into a method-selection hierarchy.
| Review type | Primary purpose | Typical scope | Methodological cue |
|---|---|---|---|
| Narrative review | Interpret and synthesise literature around a topic or question | Broad or conceptually focused literature | Flexible search, selection, and synthesis methods that may be structured without being protocol-driven |
| Systematic review | Answer a focused research question through systematic evidence synthesis | Evidence meeting predefined eligibility criteria | Explicit methods for searching, selecting, appraising, and synthesising evidence |
| Scoping review | Map the extent, characteristics, concepts, or gaps within an evidence field | Broad or heterogeneous evidence relevant to the review question | Systematic searching with evidence charting or mapping |
| Integrative review | Integrate evidence from different research designs to develop a broader understanding of a topic | Diverse empirical or theoretical literature | Combines and synthesises evidence from varied methodologies |
| Rapid review | Produce a timely synthesis of evidence for a defined information need | Focused evidence base examined under time or resource constraints | Streamlines or omits selected systematic-review processes while documenting the modifications |
| Umbrella review | Synthesise findings from existing reviews | Review-level evidence rather than a new synthesis centred on primary studies | Identifies, evaluates, and synthesises eligible systematic reviews or other reviews |
| Critical review | Critically examine and interpret literature to develop an argument or conceptual contribution | Literature relevant to critical analysis of a topic or problem | Emphasises critical interpretation and conceptual synthesis rather than one standardised search procedure |
| Systematised review | Apply elements of systematic reviewing when a full systematic review is not undertaken | A defined evidence base examined within methodological or resource constraints | Uses selected systematic-review methods without necessarily implementing the complete process |
Review categories can overlap, and their labels and methodological boundaries may vary by discipline, so these eight families should not be treated as an exhaustive taxonomy for every field.
Narrative, systematic, and scoping reviews illustrate particularly useful contrasts in purpose, scope, and methodology; the systematic narrative and scoping review differences provide a dedicated comparison of those approaches.
Narrative Literature Reviews
A narrative literature review is a flexible, interpretive synthesis used to provide context or a broad overview of a body of literature.
It can synthesise varied studies and perspectives to explain themes, concepts, or the development of a field rather than aiming for exhaustive evidence coverage.
The Journal of Graduate Medical Education describes narrative reviews as useful for complex or broad topics that require nuanced description and interpretation.
The illustration shows how a broad research question can draw on varied selected literature and lead to a thematic or conceptual synthesis, clarifying the narrative review's broad interpretive function.
A broad or conceptually oriented research question can suit a narrative review when the purpose is to interpret literature, trace themes, or develop contextual understanding.
Source selection and the search process may be less standardised, which can reduce reproducibility when methods are not reported clearly.
However, narrative reviews can use transparent and structured methods without necessarily following the full protocol-driven requirements associated with systematic reviews, and their quality depends on transparency in reasoning, source selection, and synthesis.
Systematic Literature Reviews
A systematic literature review is a structured evidence synthesis designed to answer a focused question using predefined, transparent methods.
The CDC Library describes a systematic review as an approach that collects and analyses evidence addressing a specific question, with clearly defined inclusion and exclusion criteria and a broad literature search.
Its defining methodological controls include a protocol, documented search strategy, eligibility criteria, critical appraisal, and planned synthesis.
The diagram shows these methodological controls as connected parts of a systematic review, making their role in transparent and reproducible evidence synthesis visible without presenting a full procedural workflow.
A predefined protocol specifies how the systematic review will address its focused question, while a documented search strategy and explicit eligibility criteria make evidence identification and source selection more transparent and reproducible.
Critical appraisal evaluates the included evidence, and synthesis brings eligible findings together so conclusions can be interpreted in relation to the evidence base and its limitations.
Meta-analysis may be part of a systematic review when suitable quantitative data are available, but the two terms are not interchangeable.
These methodological controls support reproducibility and confidence in how the evidence is assessed without guaranteeing objectivity; suitability for a systematic review depends on the research aim, available evidence, and required level of methodological rigour.
Scoping Reviews
A scoping review is a structured review used for evidence mapping across the breadth, characteristics, concepts, and research gaps of an evidence base, particularly when the research question is broad or the evidence is heterogeneous.
Mak and Thomas describe scoping reviews in the Journal of Graduate Medical Education as using a systematic and iterative approach to identify and synthesise literature, including mapping its extent, range, and nature and identifying gaps.
The diagram shows how a broad question can connect diverse evidence sources to mapped concepts, characteristics, and gaps.
Systematic searching identifies evidence relevant to the defined scope, while evidence charting records characteristics that can be organised through mapping-oriented synthesis to describe the evidence base, key concepts, and research gaps.
Formal critical appraisal may be absent or limited depending on the chosen scoping methodology and review purpose, rather than being universally excluded.
A scoping review may inform later focused work, but mapping the evidence can itself be the primary research purpose rather than serving merely as preparation for a systematic review.
Integrative Literature Reviews
An integrative literature review is a synthesis that brings diverse empirical literature and theoretical literature together to develop an integrated understanding of a topic.
University of Houston Libraries describes the integrative review as a method that summarises past empirical or theoretical literature and can accommodate diverse research methodologies.
Depending on the review question and methodology, this evidence diversity can include qualitative research, quantitative research, and theoretical or conceptual sources.
The illustration shows how these different evidence forms contribute to an integrated synthesis rather than being treated as interchangeable findings.
An integrative review uses transparent, defensible selection and synthesis methods to determine which evidence forms are relevant and how their different contributions can be interpreted together.
Dhollande and colleagues, writing in the Journal of Research in Nursing, describe a structured approach that includes literature searching, data extraction, critical appraisal, analysis, and an audit trail supporting reproducibility.
The defining feature is integration across diverse evidence forms, not merely the presence of both qualitative and quantitative studies.
Evidence diversity therefore supports a broader conceptual interpretation without making inclusion unrestricted or making every synthesis containing mixed research designs an integrative review.
Rapid Reviews
A rapid review is an evidence synthesis that streamlines selected systematic review methods when time constraints or resource constraints require evidence to be produced more quickly.
Stanford Lane Medical Library describes rapid reviews as knowledge syntheses that accelerate a traditional systematic-review process by streamlining or omitting specific methods to produce evidence in a more resource-efficient manner.
Time or resource pressure creates the need for faster evidence synthesis; the practical constraint is separate from the methodological choices used to shorten the review.
Selected systematic-review methods may be streamlined, such as using a narrower search scope, fewer reviewers for selected tasks, or compressed appraisal and other stages. There is no single universal package of shortcuts.
Streamlining can improve timeliness, but it may reduce comprehensiveness or change the risk of bias depending on which methods are modified.
Authors should state which methods were changed and what limitations those changes introduce rather than presenting a rapid review as equivalent to a full systematic review completed more quickly.
Smela and colleagues report that rapid-review approaches lack full methodological consensus, so the actual modifications need to be described rather than inferred from the label.
Umbrella Reviews
An umbrella review is an evidence synthesis that primarily synthesises existing systematic reviews, often including reviews with a meta-analysis, rather than using individual primary studies as its defining unit of evidence.
Cochrane describes these overviews, also called umbrella reviews or reviews of reviews, as syntheses that bring together multiple systematic reviews relevant to a decision.
What makes an umbrella review distinct
- Unit of evidence
- Existing systematic reviews, often including reviews with meta-analysis, rather than a new synthesis centred on individual primary studies.
- Best fit
- A mature evidence base containing multiple relevant reviews that can support a higher-level synthesis.
- Overlap risk
- The same primary studies can appear in several included reviews and receive disproportionate influence if overlap is ignored. Cochrane therefore advises overview authors to consider and assess overlapping reviews.
- Quality check
- Differences in conduct, reporting and reliability across included reviews need appraisal; JBI provides a critical appraisal approach specifically for systematic reviews included in umbrella reviews.
Review quality and overlap are interpreted together so the synthesis can summarise review-level evidence without assuming that it is automatically superior.
Critical Reviews
A critical review is an interpretive synthesis that evaluates a body of literature to develop an argument, identify conceptual weaknesses, or propose a new perspective.
Key distinction: critical does not mean merely negative
What the review does
It examines relationships, assumptions, tensions and limitations across the literature. It may compare competing interpretations, identify unresolved conceptual weaknesses, or combine existing ideas into a conceptual contribution.
What it is not
It is not simply a descriptive summary of what each source reports, and critical does not mean negative commentary for its own sake.
What supports a strong argument
A transparent rationale for source selection, a defensible basis for evaluation, sufficient analytical depth, and evidence and reasoning that support the interpretation.
Source selection should be explained clearly enough for readers to understand why the chosen literature supports the interpretation.
Systematised Reviews
A systematised review adopts selected systematic elements without necessarily satisfying every methodological requirement of a full systematic review.
Partial systematic adoption, not a fixed method package
Systematic elements that may be retained
- Structured searching
- Explicit inclusion criteria
- Documented source selection
- Other transparent systematic elements appropriate to the project
What may limit full implementation
- Scope
- Time
- Researcher expertise
- Assignment or project requirements
University of Melbourne Library characterises systematised reviews as using systematic approaches without meeting every requirement of a full systematic review, while University of North Carolina at Chapel Hill Libraries notes that some requirements may be reduced or omitted. The methods actually used and the constraints should be reported explicitly, because the label itself does not imply one fixed standard.
How Literature Review Types Are Classified
Literature review classification is multidimensional rather than governed by one universally accepted taxonomy.
Review forms can be distinguished by purpose, question scope, evidence source, search transparency, critical appraisal, synthesis approach, and methodological rigour.
UCLA Library explicitly notes that its review typology is not definitive or comprehensive, illustrating how category names and boundaries can shift between disciplines.
The purpose of a literature review is one classification dimension because the intended research function changes what evidence and methodology are appropriate.
Alongside purpose, question scope, evidence source, search transparency, critical appraisal, synthesis approach, and methodological rigour create distinctions in what a review does and how it is conducted; the table organises these dimensions by their typical alternatives and methodological implications.
| Classification dimension | Typical alternatives | What the dimension changes |
|---|---|---|
| Purpose | Contextual synthesis, evidence mapping, focused answering, critical interpretation | Changes the review's primary informational function and the type of synthesis required |
| Question scope | Broad or exploratory; focused or narrowly specified | Changes the breadth of eligible evidence and the methodological fit of different review approaches |
| Evidence source | Primary studies; theoretical literature; review-level evidence; mixed evidence forms | Changes the unit of evidence and the appropriate synthesis family |
| Search transparency | Flexible or selectively reported; explicit and reproducible | Changes how clearly readers can assess how evidence was identified and selected |
| Critical appraisal | Absent, limited, optional, or formally structured | Changes how evidence quality or methodological limitations contribute to interpretation |
| Synthesis approach | Narrative, thematic, conceptual, mapping, qualitative, quantitative | Changes how findings or concepts are integrated and represented |
| Methodological rigour | Flexible methods; partially systematised methods; predefined systematic methods | Changes expectations for transparency, reproducibility, and methodological control |
A review type and a synthesis technique are not necessarily the same classification.
For example, UCLA Library describes meta-analysis as a technique that statistically combines quantitative study results, while Stanford Lane Medical Library notes that meta-analysis may be used within an appropriate systematic review; a synthesis technique can therefore intersect with a review category without being synonymous with it.
Because terminology, category boundaries, and methodological expectations can vary across disciplines and published typologies, a review label should be interpreted alongside its stated purpose, evidence source, search, appraisal, and synthesis methods.
When Different Literature Review Types Are Used
The suitability of a review type depends on the research purpose, research question, question breadth, evidence maturity, required methodological transparency, and available time or resources.
Different combinations of these conditions can make different review families appropriate even when they address the same general subject.
Suitability is therefore conditional rather than a ranking in which one approach fits every research need.
The literature review research question changes the fit of a review type because its breadth and intended output shape the evidence and synthesis required.
The following conditions connect common research aims with review families that can suit them without implying a fixed selection rule.
- For an interpretive overview that develops broad contextual understanding, a narrative review can fit the research purpose.
- For a focused research question that requires explicit, reproducible methods, a systematic review can fit stronger methodological transparency needs.
- For a broad question that maps the extent, characteristics, concepts, or gaps in heterogeneous evidence, a scoping review can be appropriate.
- For a research purpose that integrates diverse empirical and theoretical evidence into one interpretation, an integrative review can fit the intended synthesis.
- For a time-sensitive evidence synthesis under tighter time or resource constraints, a rapid review can be useful when streamlined methods are reported transparently.
- For a mature evidence base containing multiple relevant existing reviews, an umbrella review can fit review-level synthesis.
- For argument-led evaluation of relationships, assumptions, or conceptual weaknesses in the literature, a critical review can support an interpretive argument or conceptual contribution.
- For a project that adopts selected systematic elements under constraints of scope, time, expertise, or project requirements, a systematised review can fit provided the methods used are stated explicitly.
The same subject can justify different review types when the research question or intended output changes.
For example, a broad question about what evidence exists across a field can point toward a scoping review, while a focused question about findings from eligible studies on the same subject can point toward a systematic review.
If the research purpose shifts toward interpreting concepts or arguments across that literature, another review type may be more suitable.
Actual suitability can also change with discipline, assignment requirements, evidence availability, methodological transparency expectations, time, resources, and researcher expertise.
These conditions should be considered alongside the intended research purpose rather than treating the review-type label as a deterministic choice.
Detailed criteria for how to choose a literature review method belong to the method-selection stage rather than this overview of typical use contexts.