Biases in Science News: Tracking Down the Source of Exaggerations

Image Credit: Public domain

Image Credit: Public domain

How often have you seen a news headline about a study on the benefits of red wine or dark chocolate only to hear later about a new study that contradicts the first one? While many science stories have strong data and evidence to back their claims, other news headlines come from the type of data that can’t provide a definitive proof of cause-and-effect. [1]. A recent study [2] looked at how journalists write science stories and how these stories can end up as misleading headline science.

The authors determined how statements made in press releases influenced the presence of exaggerations in news stories. An example would be saying that “eating dark chocolate causes fewer heart attacks” instead of indicating that there was a correlation between a group that ate more dark chocolate and the number of heart attacks occurring in that group. This study would only demonstrate a correlation between heart attacks and eating dark chocolate and does not prove that eating dark chocolate was the cause for fewer heart attacks. Researchers looked through 534 press releases prepared by research journals and the corresponding 582 news articles, then identified any statements or advice not included in the manuscript.

Results show that 25% of the press releases included more explicit advice compared to the original paper. 20% of the press releases also misinterpreted a correlation study as a study that presented a cause-and-effect relationship. The results also demonstrated that journalists would not tend to include over-exaggerations if the exaggerations were not part of the original press release.

This paper shows how exaggerations in press releases can create misleading headlines in science news stories. Since journalists may not have the expertise or time to fact-check statements from a press release, any information included in a press release should be precise, and any claims made should not be exaggerated from the original study. Headline news is crucial for communicating science, but if the stories are inaccurate or over-exaggerated, it can erode people’s trust in the scientific method.   

- Erica K. Brockmeier
Toxicology post-doc / Aspiring science writer


[1] Aschwanden, C. Science Isn’t Broken. Five Thirty Eight Science and Health (2015, Aug 19). Accessed on 2017, Feb 24.

[2] Sumner, P. et al. Exaggerations and Caveats in Press Releases and Health-Related Science News. PLoS ONE 11(12), e0168217. doi:10.1371/journal.pone.0168217 (2016).