Publication bias

by Harri Hemilä

This text is based on p 32 of Hemilä (2006)
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Harri Hemilä
Department of Public Health
University of Helsinki, Helsinki, Finland
harri.hemila@helsinki.fi

Home: http://www.mv.helsinki.fi/home/hemila

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Version May 29, 2012


One concern in meta-analyses of small studies is the possibility of ‘publication bias’ which indicates that studies with ‘negative’ findings tend to remain unpublished more often than those with ‘positive’ findings (Chalmers et al. 1990). In such cases, meta-analytical conclusions from the published trials may be too optimistic. However, in an analysis of 487 research projects approved by the Oxford Research Ethics Committee, there was evidence of publication bias in the case of observational and laboratory-based experimental studies (odds ratio [OR] 3.8 for the comparison of positive vs. negative results to be published), whereas there was no evidence of publication bias in the case of randomized clinical trials (OR 0.8) (Easterbrook et al. 1991). Thus, although publication bias is probably of concern in certain conditions, and must be kept in mind in considering the findings of a meta-analysis, its role should not be exaggerated.

References

Chalmers TC, Frank CS, Reitman D (1990) Minimizing the three stages of publication bias. JAMA 263:1392-5

Easterbrook PJ, Berlin JA, Gopalan R, Matthews DR (1991) Publication bias in clinical research. Lancet 337:867-72




Copyright: © 2006-2009 Harri Hemilä. This text is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.  

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Vitamin C and infections in animals by Harri Hemilä is licensed under a Creative Commons Attribution 1.0 Finland License.
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