Causal claims about correlations reduced in press releases following academic study of health news.

Background: Exaggerations in health news were previously found to strongly associate with similar exaggerations in press releases. Moreover such exaggerations did not appear to attract more news. Here we assess whether press release practice changed after these reported findings; simply drawing attention to the issue may be insufficient for practical change, given the challenges of media environments. Methods: We assessed whether rates of causal over-statement in press releases based on correlational data were lower following a widely publicised paper on the topic, compared to an equivalent baseline period in the preceding year. Results: We found that over-statements in press releases were 28% (95% confidence interval = 16% to 45%) in 2014 and 13% (95% confidence interval = 6% to 25%) in 2015. A corresponding numerical reduction in exaggerations in news was not significant. The association between over-statements in news and press releases remained strong. Conclusions: Press release over-statements were less frequent following publication of Sumner et al. (2014). However, this is correlational evidence and the reduction may be due to other factors or natural fluctuations.