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The effectiveness of interventions for reducing publication bias

Date and Location




Saturday 21 September 2013 - 10:30 - 12:00


Presenting author and contact person

Presenting author

Gerald Gartlehner

Contact person

Megan Van Noord
Gerald Gartlehner
Barbara Nussbaumer
Abstract text
Background: Publication bias occurs when the publication of research depends on the nature and direction of the results – a study’s positive, negative, or null result can influence its chances of publication. The non-publication of clinical trial results might mean that the findings are entirely unavailable or inaccessible, which decisively reduces the benefit of systematic reviews of drugs, medical devices, or procedures as the results from the research that is available differs from the results of all the research that has been completed in an area. This makes it difficult for clinicians, decision-makers, and patients to rely on the available evidence when making informed decisions about health care. Objectives: To evaluate the effectiveness of interventions designed and implemented to prevent and reduce publication bias related to the publishing of study results from clinical trials. Methods: A systematic literature search, completed in May 2012, was conducted in MEDLINE (via PubMed), the Cochrane Library, EMBASE, Web of Science, CINAHL, PsycINFO, and AMED databases. We manually searched reference lists of pertinent reviews, included studies, and background articles. Two independent reviewers identified studies on interventions to reduce publication bias where an analysis was performed that sought to quantify or determine the success of the intervention in reducing publication bias overall. Results: We identified 2,634 citations from searches and reviews of reference lists (Figure 1). We located 15 articles that analyzed the effectiveness of interventions to prevent or reduce publication bias in the following categories: changes in publication process (i.e., peer review process, disclosure of commercial interest, electronic publication), prospective registration of trials, open access policy, right to publication, research sponsors’ guidelines, and confirmatory large-scale trials. Conclusions: Many interventions that should supposedly reduce publication bias and that have been advocated by researchers and organizations over many years are not supported by any study data.