Publication bias promotes the invisibility of negative results from LAR

A recent survey by Dutch researchers indicates that Laboratory Animal Researchers of for-profit organizations estimated that only 10% of animal experiments are published. Respondents added that publication of processes and results or causes where no results were obtained, may increase scientific progress.

Many issues have been written and much has been said about publication bias. Now, Dutch Scientists wanted to prove it with a new study. In this case, they were convinced publication bias might also affect Laboratory Animal Research (LAR) but evidence is scarce so they made a survey to assess the opinion of laboratory animal researchers on the magnitude, drivers, consequences and potential solutions for publication bias.

Between 2000 and 3500 researchers from all animal laboratories in the Netherlands received the survey although only 474 responded. From that, 20 were excluded because of absence of data, leaving only 454 participants for the analysis.

Results show that the scientists in a for-profit environment themselves estimated that only 10 percent (5 to 50) of experiments are published. However these results change when looking at scientists in a not-for-profit institute. They estimated that about half (35 to 70) of all conducted laboratory animal experiments are published. Moreover, researchers in not-for-profit institutes reported that 80 percent (60 to 90) of their own work had been published against 10 percent (5 to 39) of the work of researchers in a for-profit environment.

Statistical non-significance and technical problems are considered to be the main drivers for non-publication. Supervisors, editors, and reviewers were all considered responsible for non-publication. Overall, respondents considered publication bias an important problem for LAR and for research duplication, literature syntheses and well-timed initiation of Phase-I clinical trials -- in humans in particular. One of the main conclusions extracted from the study shows that respondents thought mandatory publication of study protocols or results may help avoid unnecessary duplication, increase validity of literature syntheses and scientific progress, but at the cost of increased bureaucracy.

Despite these results, the experiment has several limitations. Among other reasons, authors do not know to which extent the results are representative for the Dutch LAR community, the survey was restricted to one country, only few researchers in for-profit organizations participated and study investigated researchers’ opinions, which in turn may not reflect the true rates of non-publication.

According to studies by Dr. Sena and colleagues, evidence from clinical research on humans suggests that between 46 and 67 percent of studies are not published and that in those published, positive findings are over-emphasized. Authors of this study admit Sena´s thesis: “non-publication is unethical since it deprives researchers of the accurate data they need to estimate the potential of novel therapies in clinical trials, but also because the included animals are wasted because they do not contribute to accumulating knowledge. In addition, research syntheses that overstate effects may lead to further unnecessary animal experiments testing poorly founded hypotheses”.

What can researchers do to increase the publication of negative results? Authors from this survey propose to prevent that study results have an effect on the editorial decision, to initially submit manuscripts without any results. Editors and peer reviewers would judge the importance of submissions through the background, hypotheses and methods sections. This would ensure that acceptance is not conditional on the results.

Until then, negative results appear increasingly in special journals, journal sections or repositories for negative results, such as The All Results Journals, the Journal of Negative Results in Biomedicine or Negative Results in Gynecological Oncology.

Written by Alejandro Balbuena for The All Results Journals.