Original Article
Is there a solution to publication bias? Researchers call for changes in dissemination of clinical research results

https://doi.org/10.1016/j.jclinepi.2014.06.002Get rights and content

Abstract

Objectives

To explore opinions of authors of published reports of clinical trials and Cochrane systematic reviews on the causes and methods of preventing publication bias.

Study Design and Setting

An online questionnaire was developed and sent to researchers publishing in high-impact or national general medical journals, authors of Cochrane systematic reviews, and a general population of researchers. Open-ended questions about publication bias were qualitatively analyzed. We also held a focus group with experienced researchers and/or Cochrane reviewers.

Results

Publication bias was common: 48 (36%) respondents had own unpublished trials and 40 (30%) admitted selective outcome reporting; but researchers felt strongly that blame rested also with the system that promotes and augments publication bias practices. Qualitative analysis of both survey responses and focus group discussion identified possible ways of reducing publication bias through increased transparency, improvements to trial registries, search engines and databases, enhancement of the role of institutional review boards, positive encouragement of scientists, and policy changes.

Conclusion

Although well aware of the problem, clinical researchers knowingly contribute to problems of selective reporting and nonpublication of trials. They call for changes in current practices of journal-based communication of trial reporting and for systematic evaluation of measures to decrease publication bias.

Introduction

What is new?

  • Clinical researchers from 41 countries reported high rates of nonpublication of their own trials (36%) and admitted to selective reporting of trial results (30%), confirming that publication bias remains a serious problem.

  • Researchers are aware of being the main culprits for publication bias but feel strongly that the blame rests with the system that allows such practices —from research funders and institutions to journals and trial registries.

  • To preserve the integrity and transparency of clinical research, researchers call for radical changes in the process of communicating the trial results to the professional and general public, including legal actions and alternatives to journals.

Results from clinical trials are necessary to provide unbiased information for making decisions about medical therapies and diagnostic procedures. Yet, despite the need for greater transparency of clinical research and recent strong initiatives to increase this transparency, for example, mandatory registration and posting of results from clinical trials [1], [2], there is still a long way to go before 100% of studies are published [3]. Recently updated systematic review on biases in clinical trials [4] confirmed that the extent of publication bias remains unchanged and that studies with significant or positive results are more likely to be published. The blame has been put on investigators as “almost all failure to publish is due to the failure of investigators to submit reports for publication” [5]. Even Cochrane Collaboration researchers—experts acutely aware of publication bias—publish only about a third of results presented at annual meetings [6].

Despite a number of studies investigating the prevalence and causes of nonpublication [7], [8], [9], [10], [11], investigators have not been asked about possible solutions. To address this knowledge gap and contribute to the discussion on how to achieve full transparency of clinical research [3], we used an online survey to assess how clinical researchers and Cochrane systematic reviewers explain the reasons behind publication bias and propose methods to prevent it. We further explored the themes that emerged in the survey in a focus group discussion held at a research conference on transparency in health research.

Section snippets

Survey development and data collection

A questionnaire (Appendix A at www.jclinepi.com) was developed based on previous surveys on publication bias [7]. The term “clinical trial” used in the survey was defined as “any research study that prospectively assigns human participants or groups of humans to one or more health-related interventions to evaluate the effects on health outcomes.” The types of publication bias addressed in the survey were “publication or nonpublication of research findings, depending on the nature and direction

Online survey

The response rate, up to the end of December 2012 when the survey was closed, was 8% (33 of 441) from researchers who had published in high-impact journals, 7% (21 of 310) from authors in national general medical journal, and 14% (64 of 468) for Cochrane reviewers. We also received 64 responses via the OPEN Web site. The main characteristics of the respondents are presented in Table 1. The respondents had experience in conducting clinical trials, which were mostly investigator driven and mostly

Discussion

Our study, which included authors of clinical trials and authors of Cochrane systematic reviews from 41 different countries, demonstrated that researchers are aware of being the main culprits of nonpublishing or selective publishing of results from clinical trials, as suggested by other stakeholders in the field [3], [5], [13]. However, they felt strongly that blame rested not solely with them but with the system that encourages and supports practices that lead to publication bias—from funders

Acknowledgments

Both the authors are members of the Croatian Branch of the Cochrane Collaboration. We thank the researchers who responded to the survey and who agreed to take part in the focus group discussion. We thank Dario Sambunjak, Silvano Galus, Alexandra Wieland, Elizabeth Wager, Daniel Strech, Robert Wolff, Jos Kleijnen, Hector Pardo, and Kay Dickersin for their help in creating and pretesting of the survey questionnaire.

Author contributions: A.M. designed the study, obtained the funding, contributed

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  • Cited by (0)

    Funding: This study was part of the OPEN project (Overcoming the failure to Publish Negative findings) which was funded from the European Union Seventh Framework Programme (FP7 – HEALTH.2011.4.1-2) under grant agreement number 285453.

    Conflicts of interest: The authors had support from the European Union for the submitted work; they have no financial relationships with any organizations that might have an interest in the submitted work.

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