Literature review finder: how to find reviews already written on a topic
A literature review finder is a tool or a method that finds the reviews already written on a topic: narrative literature reviews, systematic reviews, scoping reviews and meta-analyses. People use one for two different jobs, to read what is already known and to check that a review they plan has not been done, and the job decides which finder to use.
This guide separates the jobs, shows where existing reviews are listed and how to read one for the gap it leaves, and says plainly what SynthGap does as a finder and what it cannot see.
Which job is your finder for?
- Reading what is known: you want the best recent review of a topic. Search by topic, sort by date and open the newest systematic review first.
- Checking before you plan a review: you want every review, published or registered, on your exact question. Search population, intervention and outcome separately, and follow the step-by-step check.
- Finding studies for your own review: this is a search for primary studies, not for reviews, and a finder of reviews will not do it. AI search strategies covers that job.
Where existing reviews are listed
No single source lists every review. PubMed does not index every journal, and a review can sit in a language or a field that none of the sources below cover, so search at least two. Each is best for something different.
| Source | Best for |
|---|---|
| PubMed | The widest net: reviews of every type in the journals it indexes, with Review, Systematic Review and Meta-Analysis filters in its sidebar. |
| Cochrane Library | Cochrane reviews and protocols. |
| Epistemonikos | Systematic reviews, each linked to the primary studies it includes, so you can see which reviews share a study. |
| PROSPERO | Reviews with health outcomes that are registered, including ones not yet published. |
Let SynthGap run the first pass
Enter an area. SynthGap proposes candidate topics, checks each against existing systematic reviews, and lists the primary studies behind it. Start on the Free plan: no card needed, and every run shows every topic it finds.
Sign up freeLiterature review, systematic review, scoping review
The words are not interchangeable, and a finder that covers one kind can miss the others. A narrative literature review gives an author's reading of the evidence and often does not say how the studies were found. A systematic review states its question, its searches and its selection rules in advance. A scoping review maps what exists on a broad topic and does not pool results.
In PubMed, the Systematic Review filter finds systematic reviews, and the Review filter also brings in narrative reviews, so use the one that matches the kind of review you want. Systematic review or meta-analysis: which to do? explains the types.
Read a review for the gap it leaves
- Find the date of its last search. Studies published after it are not in the review.
- Read its question and its eligibility criteria. A review of adults says little about children, and a review of one outcome says little about another.
- Read its limitations and its recommendations for future research. Authors often name the gap themselves.
- Note how many studies it included and whether it pooled them. A review of three small trials leaves more room than one of thirty.
- Look for newer reviews that cite it. A later review may already have filled the gap.
How SynthGap works as a literature review finder
SynthGap looks for gaps between reviews. You describe a clinical area, and it searches an index built from PubMed and PubMed Central, proposes candidate topics for a meta-analysis, checks each one against an index of existing systematic reviews and lists the primary studies behind it.
- Systematic reviews only: it checks topics against systematic reviews. It is not a search engine for narrative literature reviews, and it does not write a literature review.
- PubMed and PubMed Central only: it does not search other databases, trial registers or the grey literature, so a review can exist that it does not see.
- AI suggestions: the topics are written by AI. A topic that looks open means not found in the index, not that nobody has done it, so run your own search of the sources above before you commit.
Questions
What is a literature review finder?
A tool or method that finds the reviews already written on a topic, rather than the single studies. Some cover only systematic reviews and others also cover narrative and scoping reviews, so check which kind a tool covers before you rely on it.
How do I find literature reviews in PubMed?
Search your topic, then use the Review, Systematic Review or Meta-Analysis filters in the sidebar, depending on the kind of review you want. Sort by date to see the newest first, and read the date of each review's last search.
Is there a free literature review finder?
PubMed and the PROSPERO register are free to search. SynthGap also has a Free plan that needs no card and covers a couple of discovery runs a month, which is enough to see how it checks a topic against existing reviews.
Can a literature review finder write my literature review?
No. A finder points you to reviews and studies, and reading them and writing the synthesis is your work. SynthGap does not write literature reviews: it suggests topics for systematic reviews and meta-analyses and shows the studies behind them.
Does SynthGap search other databases besides PubMed?
No. SynthGap's indexes are built from PubMed and PubMed Central. It does not search other databases, trial registers or the grey literature, so search the sources you need yourself before you register a protocol.
How current are the reviews a finder shows?
As current as the finder's index and as the reviews' own search dates. A review published last month may have searched its sources two years earlier, so always read the date of the last search.
Keep reading
General methodological guidance, not medical advice. SynthGap's suggestions are AI-generated from the published literature, so verify them before registering a protocol.