scid.aiCan a scoping review include a meta-analysis?
No. A meta-analysis requires quality appraisal and homogeneity of studies, which a scoping review does not assess. If the data allow pooling, that is already a systematic review.
Guide · 5 minutes
Scoping review vs systematic review: difference and choice
Both reviews require a transparent, reproducible search, but they answer different questions. A systematic review asks "does this work and how well"; a scoping review asks "what is known and how is the field organised".
Aim and type of question
A systematic review is built around a narrow question, often in PICO format: population, intervention, comparison, outcome. It exists to produce a justified estimate of an effect or association.
A scoping review takes a broad question in PCC format: population, concept, context. Its task is to show the volume and nature of research, clarify definitions and identify gaps, not to deliver a verdict.
What they share
- A protocol written in advance and explicit inclusion criteria.
- A reproducible search across several databases with saved queries.
- Two-stage screening, ideally by two independent people.
- A standardised data extraction form.
- A flow diagram of sources and reporting to the PRISMA standard.
Key differences
- Quality appraisal. Required in a systematic review: risk of bias affects the conclusions. Usually absent in a scoping review because the goal is a map, not a verdict.
- Synthesis. Systematic: quantitative (meta-analysis) or structured qualitative. Scoping: descriptive, often as tables and concept maps.
- Output. A systematic review answers the effect question with a confidence rating. A scoping review lists what has been studied, how, and where the gaps are, and often ends by recommending a systematic review.
- Reporting. PRISMA for systematic reviews, PRISMA-ScR for scoping reviews.
How to choose
If the question is narrow, the studies are comparable and you need a "does it work" answer, choose a systematic review. If the field is new, the concepts are fuzzy, the designs are heterogeneous or you first need to know whether enough research exists at all, start with a scoping review.
A common practice: a scoping review as the first stage that shows which sub-question already has enough homogeneous data for a systematic review.
Frequently asked questions
How long do both reviews take?
A scoping review usually 2–4 months, a systematic review 6–12 months or more, depending on the size of the literature and the team.
Do AI tools help at the mapping stage?
Yes: semantic search, a topic graph with clusters and an extraction table speed up mapping the field. For a systematic review, inclusion decisions and risk-of-bias assessment stay with the researchers.
Map the field before choosing a review
scid.ai shows topic clusters, years, organisations and links between papers so you can judge the volume and structure of the research.