Study Publication Bias and Outcome Reporting Bias in Clinical Trials
Author Information
Author(s): Kerry Dwan, Douglas G. Altman, Juan A. Arnaiz, Jill Bloom, An-Wen Chan, Eugenia Cronin, Evelyne Decullier, Philippa J. Easterbrook, Erik Von Elm, Carrol Gamble, Davina Ghersi, John P. A. Ioannidis, John Simes, Paula R. Williamson
Primary Institution: Centre for Medical Statistics and Health Evaluation, University of Liverpool, Liverpool, United Kingdom
Hypothesis
The study aims to review and summarize the evidence of study publication bias and outcome reporting bias in randomized controlled trials.
Conclusion
There is strong evidence that studies reporting significant results are more likely to be published and that outcomes with statistical significance have higher odds of being fully reported.
Supporting Evidence
- Studies with statistically significant results are more likely to be published.
- Statistically significant outcomes have higher odds of being fully reported.
- 40-62% of studies had at least one primary outcome that was changed, introduced, or omitted.
Takeaway
Some studies are more likely to be published if they show positive results, which can make it seem like treatments work better than they actually do.
Methodology
The study reviewed 16 cohort studies assessing publication and outcome reporting bias in randomized controlled trials.
Potential Biases
The study highlights the risk of overestimating treatment effects due to publication bias.
Limitations
The review could not separate information for RCTs from other study types in many included studies.
Statistical Information
P-Value
p<0.05
Confidence Interval
95% CI; 1.76, 5.58
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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