Extended definition
A scoping review is a structured literature synthesis whose purpose is to map what exists on a broad topic — identify key concepts, main sources, types of available evidence, and gaps — without necessarily synthesizing results or appraising quality of individual studies. It is distinguished from systematic review along four central dimensions: (1) broader scope (exploratory question, not narrow confirmatory question); (2) typical absence of risk-of-bias appraisal of studies; (3) descriptive or narrative synthesis, not meta-analytic; (4) purpose of mapping literature, not answering a specific clinical/policy question. Arksey and O’Malley’s (2005, International Journal of Social Research Methodology) methodological framework consolidated five stages: identifying the research question, identifying relevant studies, selecting studies, charting data, summarizing and reporting results. Tricco et al. (2018, Annals of Internal Medicine) published the PRISMA-ScR extension with a specific 22-item checklist for scoping review reporting, now an international standard.
When it applies
Scoping review applies in three main scenarios. First: literature is heterogeneous, broad, in early development — when it is not yet clear whether there is sufficient or appropriate evidence for a systematic review. Second: the goal is to identify gaps to inform future research or professional practice, without need for quantitative synthesis. Third: the topic crosses multiple disciplines with terminologically diverse concepts, requiring conceptual mapping before rigorous synthesis. It is a frequent precursor stage to systematic review proper, and suitable for doctoral theses in exploratory phase. Preregistration in OSF (or in fewer platforms for scoping reviews than PROSPERO offers for systematic reviews) is emerging practice.
When it does not apply
It does not apply to answering a specific clinical question about intervention efficacy — systematic review + meta-analysis is appropriate. It does not apply as a shortcut for systematic review when the question is in fact confirmatory — using scoping for effort economy when systematic rigor is needed compromises the evidence. It does not apply as a mere bibliographic survey in a thesis introduction: scoping review has formal protocol, not just broad reading. It does not replace bibliometric analysis when the goal is quantitative (volume, trends, coauthorship networks) — bibliometrics answers different questions. In fields with sparse literature, scoping may be unnecessary — narrative review is an appropriate alternative.
Applications by field
— Health: Cochrane and JBI (Joanna Briggs Institute) publish scoping reviews; public health and nursing are prolific. — Education: mapping research on pedagogical interventions, educational technology, teacher training. — Software engineering: scoping reviews on agile methods, MLOps, security — high demand in new fields. — Public policy: evidence mapping on social programs, intersectoral public health.
Common pitfalls
The first pitfall is confusing scoping with narrative: scoping review has protocol, systematic search across multiple databases, and PRISMA-ScR as reporting standard; narrative review has none of these requirements. The second is assuming scoping is “easier” than systematic — well-done it requires equivalent time, with complexity in conceptual mapping rather than quality appraisal. The third is failing to preregister the protocol: preregistration in OSF or equivalent is growing practice, although historically less rooted than in systematic reviews. The fourth is mixing functions: scoping does not answer “does intervention X work?” — for that, systematic + meta-analysis. The fifth is neglecting PRISMA-ScR in reporting: using standard PRISMA in scoping confuses readers about methodological scope and expectations; the specific extension is an editorial criterion in top-tier journals.