Intended for healthcare professionals

Letters Trial registration and publication bias

Medical journal editors and publication bias

BMJ 2013; 347 doi: (Published 22 October 2013) Cite this as: BMJ 2013;347:f6170
  1. Anne Brice, information specialist1,
  2. Iain Chalmers, coordinator1
  1. 1James Lind Initiative, Oxford OX2 7LG, UK
  1. anne.brice{at}

Wager and Williams have exposed cavalier attitudes to biased under-reporting of research among medical journal editors.1 Only 55 (28%) of 200 websites they surveyed required clinical trial registration, and some senior editors felt that trial registration would do little to reduce publication bias.

When asked what other measures might address the problem, some editors suggested having clear journal instructions to authors. In 2012, we assessed the extent to which the websites of 121 high quality clinically relevant journals included in the McMaster Online Rating of Evidence system ( contain text encouraging authors to submit reports of scientifically robust research, regardless of the direction or strength of the results. Only 14 (12%) did so.

Reporting biases lead to overestimates of beneficial effects and underestimates of harmful effects of treatments, so result in avoidable morbidity and mortality, as well as wasted resources. Biased under-reporting of research stems mainly from decisions by sponsors and researchers not to submit reports for publication.2 Many journal editors contribute to the problem, however, because they fail to make clear that they understand the scientific and ethical implications of this form of misconduct. They can contribute to reducing the problem by encouraging researchers to submit all reports of well designed research, whatever the direction or strength of the results.

Nearly three decades ago one of us (IC) proposed outlawing the term “negative trial” and suggested that all well conceived and conducted trials—whatever their results—represent positive contributions to knowledge.3 All medical journal editors should leave no doubt on their journal websites and elsewhere that they recognise the importance of publication bias, and make clear at that they and their journals support the demand for all clinical trials to be registered and reported.


Cite this as: BMJ 2013;347:f6170


  • Competing interests: None declared.


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