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The association between exaggeration in health related science news and academic press releases: retrospective observational study

BMJ 2014; 349 doi: (Published 10 December 2014) Cite this as: BMJ 2014;349:g7015

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  1. Petroc Sumner, professor12,
  2. Solveiga Vivian-Griffiths, research assistant12,
  3. Jacky Boivin, professor2,
  4. Andy Williams, lecturer3,
  5. Christos A Venetis, senior lecturer4,
  6. Aimée Davies, research assistant2,
  7. Jack Ogden, research assistant2,
  8. Leanne Whelan, research assistant2,
  9. Bethan Hughes, research assistant2,
  10. Bethan Dalton, research assistant2,
  11. Fred Boy, senior lecturer5,
  12. Christopher D Chambers, professor12
  1. 1Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff CF10 3AT, UK
  2. 2School of Psychology, Cardiff University, UK
  3. 3School of Journalism, Media & Cultural Studies, Cardiff University, UK
  4. 4School of Women’s and Children’s Health, University of New South Wales, and Graduate School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, Australia
  5. 5Department of Psychology, Swansea University, UK
  1. Correspondence to: P Sumner or C D Chambers sumnerp{at} or chambersc1{at}
  • Accepted 5 November 2014


Objective To identify the source (press releases or news) of distortions, exaggerations, or changes to the main conclusions drawn from research that could potentially influence a reader’s health related behaviour.

Design Retrospective quantitative content analysis.

Setting Journal articles, press releases, and related news, with accompanying simulations.

Sample Press releases (n=462) on biomedical and health related science issued by 20 leading UK universities in 2011, alongside their associated peer reviewed research papers and news stories (n=668).

Main outcome measures Advice to readers to change behaviour, causal statements drawn from correlational research, and inference to humans from animal research that went beyond those in the associated peer reviewed papers.

Results 40% (95% confidence interval 33% to 46%) of the press releases contained exaggerated advice, 33% (26% to 40%) contained exaggerated causal claims, and 36% (28% to 46%) contained exaggerated inference to humans from animal research. When press releases contained such exaggeration, 58% (95% confidence interval 48% to 68%), 81% (70% to 93%), and 86% (77% to 95%) of news stories, respectively, contained similar exaggeration, compared with exaggeration rates of 17% (10% to 24%), 18% (9% to 27%), and 10% (0% to 19%) in news when the press releases were not exaggerated. Odds ratios for each category of analysis were 6.5 (95% confidence interval 3.5 to 12), 20 (7.6 to 51), and 56 (15 to 211). At the same time, there was little evidence that exaggeration in press releases increased the uptake of news.

Conclusions Exaggeration in news is strongly associated with exaggeration in press releases. Improving the accuracy of academic press releases could represent a key opportunity for reducing misleading health related news.


  • We thank our professional advisory group for input into this research, including Rob Dawson (BBSRC), Fiona Fox (Science Media Centre), Ruth Francis (Biomed Central), James Gallagher (BBC), Helen Jamison (Science Media Centre), Alok Jha (The Guardian), Emma Little (The Sun), Carmel Turner (Medical Research Council), Bob Ward (Grantham Institute), and Ed Yong (National Geographic); Ananyo Bhattacharya and Simon Dymond for helpful discussions; and Eleanor-Rose Corney and Caitlin Argument for research assistance.

  • Contributors: PS, CDC, AW, JB, and FB conceived and planned the research. SV-G, AD, JO, LW, BH, and BD carried out the research, supervised by PS and CDC and funded by grants awarded to PS and CDC. SV-G, PS, CDC, CAV, and JB analysed and presented the data. PS, CDC, JB, and AW wrote the paper. PS, CDC, JB, and CAV revised the paper. PS and CDC contributed equally to this work and are the guarantors.

  • Funding: This study was supported by grants from the British Psychological Society, Experimental Psychology Society, Wales Institute of Cognitive Neuroscience, the Wellcome Trust, the Economic and Social Research Council, the Biotechnology and Biological Sciences Research Council, and Cardiff University.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare that: the study was supported by grants from the British Psychological Society, Experimental Psychology Society, Wales Institute of Cognitive Neuroscience, the Wellcome Trust, the Economic and Social Research Council, and the Biotechnology and Biological Sciences Research Council, and Cardiff University; no financial relationships with any organisations, except universities, that might have an interest in the submitted work in the previous three years; their spouses, partners, or children have no financial relationships that may be relevant to the submitted work; no other relationships or activities that could appear to have influenced the submitted work.

  • Data sharing: All coding sheets (n=462), full instructions for coding, summary data files, and analysis programs are available online (

  • Transparency: The lead authors (PS and CDC) affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

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