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Scoping Review Methodology and Evidence Map
Send your search results and abstracts, get an evidence map by cell and a stated verdict on whether the full review is warranted.
River charts every source into the grid you specify, counts the volume in each cell, and then applies a decision rule you agree before any counting happens. The rule is structural rather than numerical: a cell earns a systematic review only if it holds enough comparative studies, from enough independent research groups, measuring a common outcome. The map, the cell-level verdicts and the recommendation all come back together, with the sources behind every cell listed by identifier so a second reviewer can check the placement.
Search the query and you get method exposition: the five stages, chart the data, consult stakeholders, report against the checklist. All of it correct and none of it ending in a decision. The reporting extension is explicit about the purpose. Its own page says scoping reviews help determine whether a systematic review of the literature is warranted, and the checklist runs to twenty essential items plus two optional ones. Determining is the job. Describing the literature is the input.
Written for the doctoral student deciding whether a topic will carry a thesis chapter, the methodologist asked to scope before a funder commits, and the clinical team that needs to know if a question is answerable. Feed the retrieval from a documented search strategy. Where the answer is go, a PRISMA screening pack takes it forward. Where it is no, a synthesis organised by disagreement is the paper you write instead.
Twenty cells, 212 sources, and three cells worth reviewing
Four severity bands against five outcome domains gives twenty cells, and 212 charted sources spread across them. The rule set in advance: at least five comparative studies, from at least two independent research groups, reporting at least one outcome measure in common. Three cells clear all three conditions. Eight hold fewer than five studies, and three of those eight are empty. The remaining nine have volume and fail anyway, which is the finding a total would have hidden.
Five of those nine fail on independence. The largest cell in the whole map holds 34 sources and 29 of them, 85.3 per cent, come from two research groups. Pooling that cell would produce a confident estimate of what two teams found. The other four fail on commensurability: five or more studies each, no two measuring the same thing, so there is nothing to pool. Volume in a cell is a claim about publishing activity, not about answerability.
The three warranted cells hold 41 sources between them, 19.3 per cent of everything charted. That is the number the recommendation rests on, and it is the one to put in the abstract. The other 171 sources are still the paper. They are the evidence map, and the nine cells that failed on structure are a sharper gap statement than an empty cell, because they say the work exists and cannot yet be combined.
How it works
Fix the rule
The conditions a cell must meet to warrant a full review, agreed and recorded before any charting.
Chart every source
One row per source, placed in the grid, with the design, the group and the outcome measure recorded.
Test each cell
Volume, independence and commensurability applied cell by cell, with the failing condition named.
Return the verdict
Which cells warrant a review, which do not, and the gap statement the failures produce.
What you get
- A decision rule fixed and written down before any cell is counted, so the verdict is not retrofitted
- Volume in every cell of the grid, with the sources behind each one listed by identifier
- Independence checked per cell, because five papers from one group is one group
- Outcome commensurability checked per cell, because five studies measuring five things pool into nothing
- Empty cells reported as findings, with whether the question was asked or the design was impossible
- A stated go or no-go per cell, and the arithmetic the recommendation rests on
Common questions
Why fix the decision rule before counting anything?
Because a rule chosen after the counts is a rationalisation. Scoping the same literature with a five-study threshold and a three-study threshold gives different answers, and whichever one you pick after looking is the one that matches what you already wanted. Writing the rule first makes the recommendation contestable on the rule rather than on your motives.
Do I have to appraise study quality in a scoping review?
Critical appraisal sits differently here than in a systematic review, and the reporting extension separates essential items from optional ones. The practical consequence is that a cell's volume tells you nothing about whether the studies in it are any good. That is why the rule here tests design, independence and outcome overlap rather than counting papers.
What counts as an independent research group?
Distinct senior authorship and distinct recruitment, checked by hand rather than assumed from the author list. Overlapping cohorts are the harder case: the same participants reported in three papers is one study for pooling purposes. The run flags suspected cohort overlap with the evidence for the suspicion and leaves the call to you.
Is an empty cell a real finding?
Yes, but only once you separate two causes. A cell can be empty because nobody has asked the question, or because the design it implies is impossible or unethical. The first is a research gap worth writing up. The second is not, and reporting them together is how a gap paper loses a reviewer in the first paragraph.
How is this different from a systematic review?
A scoping review maps what exists and answers a question about the literature. A systematic review answers a question about the world and needs a narrower question, an appraisal of every included study and a synthesis. This run tells you whether the second one is currently possible, and hands off the ones that are to a screening process built for it.
Can it work from titles and abstracts alone?
Mostly. Design and population usually chart from an abstract; outcome measures and recruitment often do not. The run records the charting source per field and flags every cell whose verdict would flip if a full text contradicted the abstract. Those are the ones worth retrieving, and there are usually far fewer than thirty.
What do I get back?
A Sheet with one row per charted source and the grid alongside it, holding volume, independence, commensurability and verdict per cell. A chart of the map itself. A Doc stating the rule, the counts, the recommendation and the gap statement the failing cells produce, with every source identified.
Scoping Review Methodology and Evidence Map
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