Press releases spin uncertain findings mainly through three moves: turning association into cause, inflating animal and cell results toward human relevance, and omitting the study's limitations. A 2014 study in BMJ led by Petroc Sumner at Cardiff University analyzed press releases from 20 major British universities and found that roughly a third of releases about animal or observational studies contained exaggeration of one of these kinds — and that journalists reproduced the exaggeration at almost the same rate, rather than adding much of their own.
Engevity News publishes information, not medical advice. This piece examines the machinery of exaggeration in science communication; it evaluates no treatment and makes no health recommendation.
Where in the pipeline does spin begin?
The conventional story blames journalists, but the BMJ findings placed the introduction of exaggeration earlier, in the press release itself. University press offices face an unenviable position: they must make careful, provisional science exciting enough to cover, often within a newsroom-friendly timeframe and with an incentive structure that rewards pickup. The release is written by communicators, sometimes with the study authors' approval and sometimes with limited statistical input. When the release says a food compound in mice "may protect against" a human disease, the causal verb and the species jump are already printed. The journalist who copies the sentence has exaggerated nothing; the exaggeration was pre-packaged.
What are the recurring exaggeration moves?
The Sumner team's coding scheme distilled the problem into a small set of moves, and they remain the reader's checklist.
- Causal language for correlational studies — "X boosts Y" where the study measured association.
- Human advice inferred from animal or cell studies — diet or health guidance drawn from mice.
- Omitted limitations — small samples, short duration, unmeasured confounders unmentioned.
- Unnecessary hedging inverted — weak studies presented as established fact.
Each move survives because it makes a story simpler, and simplicity travels farther than qualification.
How do we know the releases drive the coverage?
The 2014 BMJ study was built to answer exactly that question. The researchers matched press releases to the resulting news stories and compared exaggeration rates in each. Their findings: when the release made a causal claim from a correlational study, news coverage did likewise at high rates; when the release hedged, coverage largely hedged too. Exaggeration in the release was the strongest predictor of exaggeration in the news — stronger than the outlet. A companion survey in the same paper found that most academics did not view exaggeration in releases as acceptable, and many press officers said they would welcome clearer norms, which suggests the problem is structural incentive rather than intent. Later work on press releases, including studies of inflammatory wording in cancer and neurology coverage, has repeated the pattern.
Why does the underlying paper look so different?
Because the paper was written for reviewers, the release for readers. The paper carries a limitations paragraph, a discussion of alternative explanations, and statistical language that resists causal verbs unless the design earns them. The release compresses the paper into two pages built for busy journalists on deadline, and compression strips exactly the material that made the claim honest. The gap between the two documents is measurable: hedged conclusions in the abstract can become confident declarations in the release headline. This is why reading the paper — or at least its abstract — against the release is the single highest-value habit available to a careful reader.
How can a reader spot release-driven spin?
Several signatures reveal when a news story is a release in disguise.
- The story's quotes appear in many outlets word-for-word — press releases are the only shared source.
- Only the study's own authors are quoted; no independent expert appears.
- The claim's verb is causal while the study's design, if mentioned at all, is observational.
- The species, sample size, or duration appears nowhere in the story.
A story showing two or more of these signatures was most likely rewritten from the announcement, and the announcement's incentives shaped it.
Do journals share the blame?
The press release sits at the middle of a chain that starts earlier. Journals themselves court coverage: embargoed releases, highlight emails, and public-relations staff are standard apparatus of large publishers, and studies of journal-issued materials have found the same exaggeration patterns that university releases show. The incentives align along the whole line — authors want attention for their careers, universities for their rankings, journals for citations and submissions, and outlets for readers. No single actor is dishonest, and no single actor can fix it alone. Some journals now ask authors to review press materials, and some press offices include limitations paragraphs by policy, a practice the 2014 BMJ findings directly support. For the reader, the chain's lesson is symmetry of suspicion: a bold claim deserves the same checks whether its source is a university's communications office or the journal's own publicity desk, because both are in the same business of making careful work sound exciting.
What would honest releases look like?
The BMJ paper ended constructively: exaggeration was not the press offices' preference, and tighter norms between scientists and communicators could reduce it without reducing coverage. Practices that have spread since — including explicit mention of study design and limitations in releases, and journals requiring press materials to be seen by the authors — target the exact moves the study coded. The reader-side defense is the same as ever: find the named study and year, compare the claim in the story with the claim in the abstract, and trust the abstract's verbs over the headline's. The difference between those two verbs is where the spin lives.
For more context, read Why one study is never the last word.
For more context, read how to check a health claim.
For more context, read How peer review works, and what it doesn't catch.