Direct comparison
Literature vs Systematic vs Scoping Review
How narrative, systematic, and scoping reviews differ in protocol, search rigor, and PRISMA vs PRISMA-ScR reporting — compared side by side.
Side-by-side comparison
| Dimension | Literature (Narrative) Review | Systematic Review | Scoping Review |
|---|---|---|---|
| Primary purpose | Summarize and contextualize existing knowledge on a topic, often as background for a study | Answer a focused, pre-defined research question by synthesizing all relevant evidence | Map the extent, range, and nature of evidence on a broader topic; identify concepts and gaps |
| Research question | Broad or open-ended; often not stated as a formal, structured question | Narrow and structured, typically framed with PICO or an equivalent framework | Broad and exploratory; often framed with PCC (Population, Concept, Context) |
| Protocol / registration | No fixed protocol; not typically registered | Protocol written and registered in advance, commonly via PROSPERO, before the search begins | Protocol usually pre-specified, but PROSPERO does not accept scoping-review registrations — use OSF, INPLASY, or a published protocol paper instead |
| Search strategy | Author-selected; not required to be exhaustive or reproducible | Exhaustive, reproducible search across multiple databases, documented in enough detail to be re-run | Systematic and reasonably comprehensive search, often including grey literature, but not required to be as exhaustive as a systematic review's |
| Study selection | Informal; inclusion criteria often implicit | Explicit inclusion/exclusion criteria, typically applied by two independent reviewers | Explicit eligibility criteria, typically dual independent screening — comparable rigor to a systematic review's screening stage |
| Quality / risk-of-bias appraisal | Not required; no standard tool, though SANRA offers an optional quality-of-reporting scale | Required — formal tools such as Cochrane RoB 2, ROBINS-I, or ROBIS | Not required by PRISMA-ScR; scoping reviews describe what evidence exists rather than judge its quality |
| Data synthesis | Narrative synthesis, shaped by the author's interpretation | Narrative and/or quantitative synthesis (meta-analysis) against the research question | Descriptive/tabular charting of characteristics, not pooled effect estimates |
| Reporting standard | No mandatory checklist; SANRA (6 items) available but optional | PRISMA 2020 — 27-item checklist plus flow diagram | PRISMA-ScR — 20 essential items plus 2 optional items |
| Typical output | Background/introduction section, standalone narrative article, or textbook chapter | Standalone peer-reviewed systematic review; often informs a Cochrane review or clinical guideline | Standalone evidence map, often used to scope the feasibility of a subsequent systematic review |
| When to choose it | Providing background/context, or where too little evidence exists yet for formal synthesis | The question is narrow and answerable, and enough primary studies exist to synthesize | The literature is broad, heterogeneous, or emerging, and the goal is mapping rather than answering one question |
Common questions
FAQ
Is a scoping review a type of systematic review?+
No. Both use systematic, documented search and screening methods, and PRISMA has a reporting extension for each, but a scoping review answers a different kind of question (what evidence exists, and in what form) and does not require the quality/risk-of-bias appraisal that defines a systematic review. It is better described as a distinct review type that borrows systematic-review rigor at the search stage, not a subtype of a systematic review.
Can I register a scoping review with PROSPERO?+
No. PROSPERO does not accept scoping-review protocols — it is scoped to systematic reviews (plus rapid and umbrella reviews) with a health-related outcome. Scoping-review protocols are commonly registered instead via the Open Science Framework (OSF), INPLASY, or published as a standalone protocol paper.
Does a literature review need to follow PRISMA?+
No. PRISMA 2020 applies to systematic reviews and PRISMA-ScR to scoping reviews. A narrative/literature review has no PRISMA reporting obligation. If a journal or supervisor wants a lightweight quality check anyway, SANRA (Scale for the Assessment of Narrative Review Articles) is the closest equivalent, though it is optional and far less commonly enforced than PRISMA.
Which review type should I choose if I am not sure my question is narrow enough yet?+
A scoping review is often the right starting point. Its purpose is explicitly to map a body of literature and clarify concepts, which can tell you whether a narrow, answerable question — and enough primary studies — exists to justify a subsequent systematic review.
