Is my meta-analysis topic novel?

A topic is novel when answering it adds something that is not already available to readers. That does not mean no review exists on the subject. It means no reliable, current review answers the specific question you plan to ask.

This distinction matters, because treating any existing review as a reason to stop throws away good topics, while ignoring existing reviews produces redundant ones.

What counts as novel

A question nobody has pooled: a population, intervention, comparator or outcome combination with no systematic review.
A new population or setting for a known question, for example children, older adults, or a low-income setting, where the existing reviews do not apply.
A different outcome: harms, quality of life or long-term follow-up when earlier reviews covered only the main efficacy outcome.
A substantial amount of new evidence since the last search, enough that it could change the conclusion.
A clearly more reliable method: for example restricting to randomized trials, using individual patient data, or fixing a flaw in an earlier review.

What does not count

The same question and the same studies, reported again.
A small change to the question (adding one drug to a class, one extra year of publication) that leaves the answer where it was.
A review that adds one or two studies to a conclusion that is already clear and unlikely to change.

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. The free plan includes 3 discovery runs a month.

Start free

When a review already exists: skip, update, extend or proceed

Find the closest existing review and read its search date, its question and its included studies.
Judge its reliability. Tools such as AMSTAR 2 and ROBIS are designed to assess the quality and risk of bias of systematic reviews.
If it is recent, reliable and answers your exact question, skip the topic or look for an adjacent question.
If it is reliable but out of date and new studies are likely to matter, an update, or a living review, can be justified.
If it is reliable but narrower than your question (different outcome, population or comparator), extending it is novel.
If it is unreliable or answers a different question, a new review can be justified. Say exactly why in your protocol.

How to check

Search more than one source, for the question and for the outcome separately, and look at registered protocols as well as published reviews. The step-by-step guide to checking whether a systematic review already exists covers the search.

Record the date and the search terms. A reviewer or editor will ask.

Questions

How recent does a review have to be to count as up to date?

There is no fixed rule. In fast-moving fields a review a few years old can already be out of date, while in slow-moving ones it can stand for longer. What matters is whether new studies have appeared that could change the conclusion.

Should I check registered protocols too?

Yes. A protocol on PROSPERO or another register means someone else is already doing the review, even if it is not yet published.

Is a living systematic review a good choice?

It can be, for fast-moving questions where new studies keep appearing. It needs a team that can commit to repeated updating.

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.