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Open Access Highly Accessed Open Badges Commentary

A proposal for reducing the effect of one of many causes of publication bias

Sue M Richards and Julie A Burrett*

Author Affiliations

Clinical Trial Service Unit (CTSU), Richard Doll Building, Old Road Campus, Roosevelt Drive, Oxford, OX3 7LF, UK

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Trials 2013, 14:41  doi:10.1186/1745-6215-14-41

The electronic version of this article is the complete one and can be found online at:

Received:26 March 2012
Accepted:28 January 2013
Published:12 February 2013

© 2013 Richards and Burrett; licensee BioMed Central Ltd.

This 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.


In order to avoid publication bias, all trials should be registered at initiation and their results made easily accessible. However, some trial results are more difficult to publish than others. This report describes one such trial and highlights the need for a way of making results of trials widely available even if not presented in the traditional format. Until such time as it is required by law both to register all trials and enter their final results into the database, a lack of resources will mean that some trial results are never published. The scale of the problem of non-publication is unknown and for valid trial results any form of publication is better than none. Therefore it is essential that a quick and easy way is available to act as a safety net to catch trial results that would otherwise be lost.

Publication bias; Randomized trial; Polycythaemia; Busulphan; Radioactive phosphorous; Venesection


The problem of publication bias in scientific research has been recognized for many years, and was drawn to the attention of the medical community in the 1980s [1]. Since that time many studies have shown that lack, or delay, of publication is related to the statistical significance of the results [2-7]. Awareness of this has been increased by the rise in systematic reviews, and methods to assess the degree of publication bias in these have been developed [8]. These methods provide a rating of the quality of the evidence but do not help in determining a corrected effect estimate.

Some measures have already been put in place to address the problem, such as the requirement that trials must have been registered in a recognized public trials registry at initiation as a condition of consideration for publication in a journal that is a member of the International Committee of Medical Journal Editors [9]. Even for trials which have been registered, publication rates are low [10].

We discuss here one example that illustrates that there may be additional ways of reducing this problem.

Main text

The Medical Research Council funded a randomized trial in polycythaemia (Figure 1), which recruited between 1974 and 1993, before the days of trial registries. Due to the low mortality rate from this disease, with a median survival of 13 years, follow-up continued until 2003. During this time personnel working on the trial changed, including the departure of the statistician. This trial then came under the remit of the remaining statistician in the Clinical Trial Service Unit responsible for leukemia trials, who reran analyses and wrote a skeleton paper. The introduction, methods and results sections of the paper were drafted, but the discussion section was incomplete and the clinical lead then retired. The computer system on which the analysis programs ran has now been superseded. Although programs and data have been archived it would take a considerable amount of work to do any further analyses.

thumbnailFigure 1. Randomization structure showing the number of patients allocated to each of the three treatments (Venesection, P32 and Busulphan) and the method of treatment allocation in each phase of the trial. Vn1, Pn2 and Bn3 indicate that n1 patients were allocated to Venesection, n2 to P32 and n3 to Busulphan.

The paper remains without an abstract, discussion section or references and there are no resources available for any further work to be done. The trial was completed and we strongly believe that the results should be made publicly available. However, we have not found any journal that would accept the paper in this format (see Additional file 1: Medical Research Council randomized Polycythaemia trial results: long term outcome after busulphan, radioactive phosphorous or venesection).

Additional file 1. Medical Research Council randomized Polycythaemia trial results: long term outcome after busulphan, radioactive phosphorous or venesection.

Format: DOC Size: 176KB Download file

This file can be viewed with: Microsoft Word ViewerOpen Data


Much recent discussion has focused on the issue of competing, particularly financial, interests, and the role of the pharmaceutical industry. This has led to a new US law requiring both the registration of trials and the entry of final results into a database [11], and the suggestion that legislation should be expanded internationally [12]. However, there are other reasons behind non-publication, including a lack of resources, as in the example presented here.


The scale of the non-publication of trials is unknown, but providing a medium for reporting unpublished trials, together with any results that are available from them, would provide further information on this subject.

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

SR wrote the first draft of the commentary, JAB revised it, and both authors read and approved the final manuscript.


Thank you to Iain Chalmers and Doug Altman for encouragement to report this trial, and for the suggestion to write this commentary.


  1. Begg CB, Berlin JA: Publication bias: a problem in interpreting medical data.

    J Roy Stat Soc A 1988, 151:445-463. OpenURL

  2. Dickersin K: The existence of publication bias and risk factors for its occurrence.

    JAMA 1990, 263:1385-1389. PubMed Abstract | Publisher Full Text OpenURL

  3. Dickersin K, Min YI, Meinert CL: Factors influencing publication of research results. Follow up of applications submitted to two institutional review boards.

    JAMA 1992, 267:374-378. PubMed Abstract | Publisher Full Text OpenURL

  4. Easterbrook PJ, Berlin JA, Gopalan R, Matthews DR: Publication bias in clinical research.

    Lancet 1991, 337:867-872. PubMed Abstract | Publisher Full Text OpenURL

  5. Dwan K, Altman DG, Arnalz JA, Bloom J, Chan A-W, Cronin E, Decullier E, Easterbrook PJ, von Elm E, Gamble C, Ghersi D, Ioannidis JPA, Simes J, Williamson PR: Systematic review of the empirical evidence of study publication bias and outcome reporting bias.

    PLoS One 2008, 3:e3081. PubMed Abstract | Publisher Full Text | PubMed Central Full Text OpenURL

  6. Burrett JA, Lunn D: Analysis of characteristics of randomized clinical trials in leukaemia that are associated with how results are reported.

    JEBM 2011, 4:217-224. OpenURL

  7. Paulson K, Saeed M, Mills J, Cuvelier GDE, Kumar R, Raymond C, Robinson T, Szwajcer D, Wall D, Seftel MD: Publication bias is present in blood and marrow transplantation: an analysis of abstracts at an international meeting.

    Blood 2011, 118:6698-6701. PubMed Abstract | Publisher Full Text OpenURL

  8. Guyatt GH, Oxman AD, Montori V, Vist G, Kunz R, Brozek J, Alonso-Coello P, Djulbegovic B, Atkins D, Falck-Ytter Y, Williams JW Jr, Meerpohl J, Norris SL, Akl EA, Schünemann HJ: GRADE guidelines 5: rating the quality of evidence - publication bias.

    J Clin Epidemiol 2011, 64(12):1277-82.

    Dec, Epub 2011 Jul 30

    PubMed Abstract | Publisher Full Text OpenURL

  9. De Angelis C, Drazen JM, Frizelle FA, Haug C, Hoey J, Horton R, Kotzin S, Laine C, Marusic A, Overbeke AJPM, Schroeder TV, Sox HC, Van Der Weyden MB: Clinical trial registration: a statement from the International Committee of Medical Journal Editors.

    Lancet 2004, 364:911-912. PubMed Abstract | Publisher Full Text OpenURL

  10. Ross JS, Mulvey GK, Nissen SE, Krumholz HM: Trial publication after registration in a cross-sectional analysis.

    PLoS Med 2009, 6(9):e1000144. PubMed Abstract | Publisher Full Text | PubMed Central Full Text OpenURL

  11. Tuma RS: New law may be having some effect on publication bias.

    JNCI 2010, 102:290-292. PubMed Abstract | Publisher Full Text OpenURL

  12. Bian Z-X, Wu T-X: Legislation for trial registration and data transparency.

    Trials 2010, 11:64-66. PubMed Abstract | BioMed Central Full Text | PubMed Central Full Text OpenURL