Category: Publication bias. Publication bias is the tendency for researchers who have data with a negative conclusion to fail to publish their work. These pages discuss the problems that publication bias causes, especially for those researchers who are performing a systematic overview. Articles are arranged by date with the most recent entries at the top. You can find the theme and closely related categories and other resources at the bottom of this page.

Stats: Registration of clinical trials (July 22, 2005). International Committee of Medical Journal Editors (ICMJE) has called for a requirement for registration of clinical trials. All clinical trials that start recruiting on or after July 1, 2005 must be placed in a public registry before enrollment of the first patient. This includes "trials that test a clinical hypothesis about health outcomes" but not phase 1 trials that only assess toxicity and/or pharmacokinetics.

Stats: Publication bias (June 25, 2004). Eliot Spitzer, New York's state attorney general has filed a lawsuit against GlaxoSmithKline for concealing negative trials about an antidepressant that the company manufactures (Paxil).

Stats: Publication Bias references (June 25, 2004). Publication bias is the tendency for negative research to get published less frequently, less prominently, or more slowly, and the tendency for positive research to get published more than one time. Here are some references that document the problems caused by publication bias.

Stats: Selective reporting of research findings (March 14, 2005, Evidence, Clinical importance). I have talked extensively about publication bias in my weblog and address this issue in detail on my book on Statistical Evidence which I hope to finish sometime soon. A related problem is when researchers decide to report or not report particular data analyses based on how impressive the results appear. This is called publication bias in situ (PBIS) by Phillips 2004, Publication bias in situ. Phillips CV. BMC Med Res Methodol 2004: 4(1); 20.

Stats: A serious problem of publication bias (April 9, 2004). I was browsing a paper by Leonard Leibovici about alternative medicine when a comment by Andrew Vickers  in the eletters section caught my eye. He noted the serious problem of publication bias in Chinese journals. Apparently, the Chinese journals almost never publish a negative trial. He cites two sources: Vickers et al 1998 CCT and Tang et al 1999 BMJ.

Theme and closely related categories:

• Theme: Evidence based medicine

• Category: Systematic overviews

Other resources

• Bias in location and selection of studies Description: This article reviews publication bias and several related types of bias, including language bias, database bias, and inclusion bias.
• Clinical trial registration: looking back and moving ahead
• Clinical Trials Reporting and Publication. CRS Report for Congress. Excerpt: The central issue before Congress with respect to clinical trials reporting and publication is how to balance the potential beneficial public health effects of requiring that clinical trials data be made public with the burdens that such requirements may place on companies and their innovation. Clinical trials, which are conducted regularly to test the effects of new pharmaceuticals and medical devices, cost a significant amount of money, and by their nature may present some risk to the people who participate in them. Manufacturers as well as medical journal editors have been reluctant to publish clinical trial data indicating that products in development are harmful or ineffective. The availability of such information might save a duplication of effort and studies that harm or fail to help patients.
• Cholesterol lowering trials in coronary heart disease: frequency of citation and outcome Description: This article examines 22 cholesterol lowering trials and found that positive trials were cited six times more frequently. This illustrates a tendency for researchers to preferentially cite trials that support the prevailing viewpoint.
• Commentary: Searching for Trials for Systematic Reviews: What Difference Does it Make?
• Current Controlled Trials: an opportunity to help improve the quality of clinical research Description: This articles describes a new journal, Current Controlled Trials in Cadiovascular Medicine, that encourages registration of all trials, reporting both positive and negative trials, and using systematic reviews to set the direction for future research.
• Determinants of abstract acceptance for the Digestive Diseases Week--a cross sectional study.
• Do certain countries produce only positive results? A systematic review of controlled trials
• Does the inclusion of grey literature influence estimates of intervention effectiveness reported in meta-analyses?
• Electronic trial banks: a complementary method for reporting randomized trials
• Empirical assessment of effect of publication bias on meta-analyses
• Empirical Evidence for Selective Reporting of Outcomes in Randomized Trials: Comparison of Protocols to Published Articles
• Estimating effect sizes: Bias resulting from the significance criterion in editorial decisions
• Evaluating the quality of articles published in journal supplements compared with the quality of those published in the parent journal
• Evidence-based practice: extending the search to find material for the systematic review
• The existence of publication bias and risk factors for its occurrence
• Factors influencing publication of research results. Follow-up of applications submitted to two institutional review boards
• Fair conduct and fair reporting of clinical trials
• GlaxoSmithKline faces US lawsuit over concealment of trial results
• How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Empirical study
• How useful are unpublished data from the Food and Drug Administration in meta-analysis?
• Impact of covert duplicate publication on meta-analysis: a case study
• Impact of FUTON and NAA bias on visibility of research Description: The article examines journals with full text on the net (FUTON) and found that they had higher impact factors after converting to FUTON.
• Language bias in randomised controlled trials published in English and German Description: This article found articles published in German which had a matching article published by the same author at about the same time, but using a different data set and published in English. In 62% of the English language articles, but only in 35% of the German language articles were there reports of a statistically significant finding (P<.05).
• Meta-analysis and the meta-epidemiology of clinical research. Registration of trials should be required by editors and registering agencies [letter; comment]
• Minimizing the three stages of publication bias
• Misleading funnel plot for detection of bias in meta-analysis
• More insight into the fate of biomedical meeting abstracts: a systematic review
• Multiple Publication of reports of Drug Trials
• Operating characteristics of a rank correlation test for publication bias
• Peer-reviewed publication of clinical trials completed for pediatric exclusivity Description: This article examines research conducted under a new FDA rule, pediatric exclusivity, that offers a financial incentive for drug companies to produce research in pediatric populations for drugs that are approved for adults. A large amount of the research conducted under this rule remains unpublished.
• A plan to register unpublished studies [news]
• Positive-Outcome Bias and Other Limitations in the Outcome of Research Abstracts Submitted to a Scientific Meeting
• Publication and related bias in meta-analysis: power of statistical tests and prevalence in the literature
• Publication bias and clinical trials
• Publication bias and meta-analysis
• Publication Bias and Research on Passive Smoking: Comparison of Published and Unpublished Studies
• Publication bias: evidence of delayed publication in a cohort study of clinical research projects
• Publication bias in clinical research
• Publication bias in gastroenterological research - a retrospective cohort study based on abstracts submitted to a scientific meeting.
• The Quality of Drug Studies Published in Symposium Proceedings
• Quasireplication and the contract of error: lessons from sex ratios, heritabilities and fluctuating asymmetry Description: This article promotes the use of funnel plots to identify selective reporting. The authors also encourage the use of true replication in research rather than quasireplication, replicating in a similar, but not identical species and systems.
• Randomized clinical trials: what gets published, and when?
• Redundant Publication: A Reminder
• Registering Clinical Trials
• Retrospective and prospective identification of unpublished controlled trials: lessons from a survey of obstetricians and pediatricians
• Review of randomised controlled trials of traditional Chinese medicine
• The risk of bias from omitted research: Evidence must be independently sought and free of economic interests
• Role of a research ethics committee in follow-up and publication of results
• Scientific quality of original research articles on environmental tobacco smoke
• Selecting the language of the publications included in a meta-analysis: is there a Tower of Babel bias?
• Systematic reviews in health care: Investigating and dealing with publication and other biases in meta-analysis
• Time to publication of studies was not affected by whether results were positive [letter; comment]
• Trial Registration at ClinicalTrials.gov between May and October 2005 Description: This article reviews trials registered at ClinicalTrials.gov after a mandate by the International Committee of Medical Journal Editors to refuse publication of unregistered trials. While there was an increase in the number of trials published and the completeness of information provided, the information provided by major drug companies was still largely insufficient to make the registry useful.
• Underreporting research is scientific misconduct
• Under-reporting of clinical trials is unethical
• Unpublished Research from a Medical Specialty Meeting: Why Investigators Fail to Publish
• Visibility of research: FUTON bias
• What contributions do languages other than English make on the results of meta-analysis?

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This webpage was written by Steve Simon on 2007-06-19, edited by Steve Simon, and was last modified on 2008-07-14. Send feedback to ssimon at cmh dot edu or click on the email link at the top of the page.