When you face a broad research topic, a scattered literature, or a question nobody has mapped yet, a scoping review is often the right tool. Instead of testing whether one intervention works, it charts what research exists, how it has been studied, and where the gaps remain. Done well, it gives other researchers a reliable map of the field and gives you a strong foundation for a thesis, a grant proposal, or a later systematic review.
This guide walks through the whole process in order: framing a question, writing a protocol, searching systematically, screening studies, charting data, synthesising findings, and reporting them clearly.
A scoping review is a type of evidence synthesis that maps the key concepts, types of evidence, and research gaps in a defined area. Its question is deliberately broad. Rather than asking whether a treatment is effective, it asks what is known about a topic, how that knowledge has been produced, and what remains unexplored. The output is a structured map of the literature, not a single verdict.
Scoping reviews are especially useful in emerging fields, in topics studied with many different methods, and where terminology is still unsettled.
The clearest contrast is with a systematic review. A systematic review starts from a narrow, focused question, applies strict eligibility criteria, appraises study quality, and synthesises results to answer that question, sometimes with a meta-analysis. A scoping review starts broader, includes a wider range of study designs and sources, and summarises findings descriptively instead of pooling them into one estimate.
A narrative review differs again: it is usually written by experts drawing on selected literature, without a pre-specified search or selection method that another researcher could repeat. A scoping review, by contrast, must be systematic in its methods even though its question is broad.
Choose a scoping review when your aim is to map rather than to judge. Good reasons include exploring a new or fast-moving field, clarifying how a concept is defined and used, surveying the range of methods applied to a problem, identifying gaps before designing a primary study, or deciding whether a full systematic review is feasible and worthwhile. It is also a sound choice when the literature spans disciplines that use different terms for the same idea.
Do not choose one when you need a definitive answer about effectiveness, safety, or a recommendation for practice. Those questions need a systematic review, with quality appraisal and careful synthesis of comparable studies.
Scoping reviews commonly frame the question with PCC: Population, Concept, and Context. Population is who or what the review concerns, such as a patient group, an animal species, or a type of practitioner. Concept is the main idea under study, such as an intervention, a method, or a phenomenon. Context is the setting or circumstance, such as a country, a health system, a farming system, or a time period. Defining all three keeps a broad question bounded.
Turn your PCC elements into one main question plus a small set of sub-questions. The sub-questions might ask which populations have been studied, which methods dominate, and where evidence is thin. Keep the question open enough to capture the field, but specific enough that screening decisions are possible.
Write your protocol before searching. It should record the review question and sub-questions, the PCC elements, inclusion and exclusion criteria, the sources you will search, the search approach, the screening process, the charting form, and how you will summarise findings. Writing these decisions down in advance protects you from quietly shifting the scope midway because early results look inconvenient.
Registering the protocol on an open platform such as the Open Science Framework makes your plan public and time-stamped. That is acceptable, provided every change is documented, dated, and explained in the final report rather than silently absorbed into the method.
A scoping search must be systematic even though the question is broad. Start by listing the core concepts from your question and gathering synonyms, spelling variants, and related terms for each. Combine them with Boolean operators, use subject headings where the database offers them, and test the strategy against a small set of known relevant papers to check that it retrieves them.
Search several subject databases relevant to your field, and consider grey literature such as reports, theses, conference proceedings, and organisational publications where they matter to your topic. Record the full search strategy for at least one database, the date each source was searched, and any limits applied, such as language or publication type.
Screening usually happens in two stages: titles and abstracts first, then full texts of the records that survive. Two reviewers should screen independently at each stage, with disagreements resolved by discussion or by a third reviewer.
Before the full screen, pilot the eligibility criteria on a small sample so reviewers can align their judgements and clarify ambiguous rules. Keep a record of how many records were excluded at each stage and why, because that record becomes the flow diagram in your report.
In scoping reviews, data extraction is called charting, and the distinction matters. You are not pulling out effect sizes for a meta-analysis; you are recording the characteristics of each study in a consistent form so patterns and gaps become visible. Typical charting fields include author and year, setting, population, concept studied, method, and key findings, plus any field tied to your sub-questions.
Draft the charting form from your question, pilot it on a few included studies, and revise it before charting the full set. Two reviewers should chart independently or with verification, depending on your protocol, and disagreements should be resolved by discussion.
Synthesis in a scoping review is descriptive. Count and summarise what you charted: how many studies used each method, which populations and settings appear most, how the topic has been studied over time, and where coverage is thin. Present these patterns in tables and simple charts, and support them with a narrative that explains what the pattern means rather than merely repeating the numbers in words.
You may also group findings thematically, for example by concept definition, by method, or by setting, to show how different parts of the field relate. The review maps the evidence; claims about what works require a different design, and overstating your synthesis is one of the fastest ways to lose a reviewer's confidence.
Report your review using the PRISMA extension for scoping reviews, known as PRISMA-ScR. Its checklist covers the title and abstract, the rationale and objectives, the protocol and any registration, eligibility criteria, information sources, the full search strategy, the selection process, the charting method, and the synthesis approach, followed by results, limitations, and funding. Working through the checklist as you draft prevents the common problem of a strong review undermined by missing method detail.
Include a flow diagram showing records identified, screened, excluded, and included, with reasons for exclusion at the full-text stage. Transparency about limits strengthens a scoping review; hiding them weakens it.
Several mistakes recur in weak scoping reviews. The question is either so broad that screening becomes unmanageable or so narrow that the review is a systematic review in disguise. Only one reviewer screens or charts, with no check on consistency. The search is undocumented, so nobody can tell whether it was comprehensive or merely convenient.
Other frequent problems include presenting charted data without synthesis, so the reader gets a catalogue instead of a map, and drawing effectiveness conclusions the design cannot support. Watch also for red flags in the publishing world: any journal or service that offers a guaranteed acceptance or a guaranteed publication timeline should be treated with caution. Before submitting anywhere, run the checks in our guide on how to avoid predatory journals.
Suppose your team wants to map how telemedicine is used in veterinary outreach to remote farming communities. The PCC framing might be: Population — veterinary practitioners and livestock keepers; Concept — telemedicine services, including remote consultation and diagnostic support; Context — outreach to remote or underserved farming areas. Sub-questions could ask which services are described, which technologies are used, and which barriers practitioners report.
Working through the method, the team would write a protocol, search veterinary, medical, and agricultural databases plus relevant grey literature, and screen in duplicate. The synthesis would then show which services and settings dominate the literature, where evidence is sparse, and which questions a focused follow-up review could answer — a map, not a verdict on whether telemedicine works.
Use this checklist before you consider the review complete, and ask a colleague to run through it independently:
Structure the manuscript like other research articles, but let the method carry the weight. The introduction should explain why a mapping review was needed, what is already known, and what gap the review addresses. The methods section must be detailed enough to repeat: question, protocol, eligibility criteria, sources, search, selection, charting, and synthesis.
In the results, lead with the flow of studies and the overall shape of the evidence, then present each sub-question in turn with its table or chart. End with a conclusion that summarises the map, not a recommendation the design cannot justify.
When the manuscript is ready, choose a journal whose scope fits a mapping review in your field, and read its author guidelines before formatting. Our guide on how to choose the right journal for your research paper explains how to build a shortlist. If your review concerns veterinary or animal sciences, check the animal sciences manuscript guidelines and the journal scope on our journals page.
Global Academic Publishers publishes the Global Journal of Veterinary and Animal Sciences, an open access journal with double-blind peer review; its ISSN and DOI are still in application. Learn how that review model works in double-blind peer review explained, and prepare your manuscript file with no author details inside it where double-blind review applies. A complete, transparent methods section is the strongest asset your submission can have.
| Feature | Scoping review | Systematic review | Narrative review |
|---|---|---|---|
| Question | Broad, often framed with PCC | Narrow and focused | Broad, author-defined |
| Purpose | Map evidence and gaps | Answer a specific question | Summarise selected literature |
| Protocol | Written in advance, changes documented | Written in advance, changes documented | Usually not pre-specified |
| Search | Systematic and repeatable | Exhaustive and repeatable | Selective, often unreported |
| Quality appraisal | Generally not required | Required | Not standard |
| Synthesis | Descriptive, tabular and thematic | Narrative or meta-analysis | Author narrative |
| Output | Evidence map and research agenda | Conclusion or recommendation | Expert overview |
These authoritative external resources explain the standards and tools mentioned in this guide:
What is the difference between a scoping review and a systematic review?
A scoping review maps the breadth of evidence on a broad topic and identifies gaps, while a systematic review answers a narrow question, usually about effectiveness, and synthesises findings to reach a conclusion. Scoping reviews use a broad question and descriptive synthesis; systematic reviews use a focused question and often include quality appraisal and, where appropriate, meta-analysis.
Do I need to assess the quality of studies in a scoping review?
Formal quality appraisal is generally not required in a scoping review, because the aim is to map what exists rather than to judge how trustworthy each effect estimate is. If you do appraise quality, state your tool and rationale clearly, and do not exclude studies on quality grounds unless your protocol said you would.
How long does a scoping review take?
There is no fixed duration: it depends on the breadth of the question, the volume of literature, the size of the team, and how many rounds of screening and charting are needed. A small, well-bounded review by an experienced team moves faster than a broad review of a large, messy literature, so plan in stages and pilot each step before scaling up.
Should I write and register a protocol for a scoping review?
Yes. A protocol records your question, eligibility criteria, sources, search approach, screening process, and charting plan before you begin, which keeps decisions consistent and transparent. Registering it on an open platform such as the Open Science Framework makes the plan public and lets readers see any changes you made along the way.
How many databases should I search for a scoping review?
There is no single correct number. Search enough subject databases and grey literature sources to cover your field, justify each source in your protocol, and record your full search strategy so another researcher could repeat it. A librarian or information specialist can help you choose sources and build a strategy that is broad without being unmanageable.
Can I write a scoping review on my own?
You can lead one, but independent duplicate screening and charting by at least two reviewers is the expected standard, so a small team is strongly recommended. If you work alone, be transparent about it, use careful piloting and checking, and acknowledge the limitation in your report rather than presenting a single-reviewer process as equivalent.