Inside trials: an interview study of clinical trials and trial reporting

Inside Trials Study

Results of clinical trials are often not published. We were interested in finding out how this comes about, and what past trial participants and others think about it.

It is estimated that about 4 in every 10 randomized controlled trials are not published in academic journals or only published after a long delay. Clinical studies with unfavourable results for the tested drug are less likely to be published—a phenomenon known as publication bias. When trial results are not published, this makes it more difficult to understand the risks and benefits of drugs. This has led to less informed patient care and unnecessary harm to patients. 

We conducted a research study called “Inside trials: an interview study of clinical trials and clinical trial reporting.” The aim of this qualitative study was to examine factors that contribute to nonpublication of clinical trials in Canada and related ethical issues.

This University of British Columbia study was based on interviews with 34 participants, including 10 clinical trial participants, 17 clinical trial investigators, 1 clinical research coordinator, 3 research administrators, and 3 research ethics board members. Interviews for the study were conducted between March 2019 and April 2021.

Trialists who participated were from a range of medical fields, including cardiovascular medicine, endocrinology, hepatology, infectious diseases, oncology, psychiatry, and rheumatology. Trial participants had taken part in trials of treatments for cardiovascular disease, C. difficile infections, chronic pain, diabetes, eye disorders, and multiple sclerosis. Participants were from the Canadian provinces of British Columbia, Alberta, and Ontario.

Reporting our study findings

This research study produced findings on three main issues:

  • Industry sponsor influence on whether the results of clinical trials are reported
  • Factors, other than industry influence, relating to whether results of clinical trials are reported
  • Reporting of clinical trial results as an ethical responsibility to research participants.

Findings on these issues will be reported in separate academic journal articles. As the results are published, key findings will also be reported on this website and links to abstracts or full articles will also be reported.

To date, we have reported our findings on the first of these issues—industry sponsor influence—in the journal Clinical Therapeutics. An abstract for this article is available on the journal’s website. While the final article is only available to the journal’s subscribers at this time, the accepted manuscript and an appendix with additional information may be downloaded from this site. Clinical Therapeutics also published an editorial accompanying our article in which it pledged to address scientific bias in its publications.

The results of our study, covering all of the issues listed above, are reported in the main researcher’s PhD dissertation, “Nonpublication and publication bias in clinical trials in Canada: a qualitative interview study,” which is available for download from University of British Columbia’s cIRcle repository.

Industry sponsor influence in clinical trial reporting: key findings

We found that industry sponsors of clinical trials have a weaker incentive to report the results of certain trials, including those with unfavourable results for the tested drug and those for drugs they have decided not to market.

Interviews with trial investigators and others highlighted mechanisms through which sponsors may influence whether a trial is reported:

  • First, sponsors may influence reporting by stopping a trial early and not proceeding to publish the findings.
  • Second, sponsors typically own and may control access to the key data from a trial, which may be an obstacle to investigators reporting trial results if the sponsor does not support publication.
  • Third, sponsors may negotiate clinical trial agreements in multicentre trials which do not protect the ability of site investigators to publish based on all of the data from a trial if the sponsors and trial leaders do not proceed with publication.

Early phase internal company trials of investigational drugs are an additional source of unpublished trials. Importantly, dependence of researchers and research centres on funding from industry sponsors may weaken their ability to negotiate terms with industry sponsors that fully protect the right of investigators to publish findings.


We would like to express our gratitude to everyone who was willing to take part in this study and to discuss their views and experiences, without whom this research would not have been possible. In addition, we would like to thank the clinical research coordinators who helped with recruitment for the study by seeking consent from past trial participants for us to contact them about the study, and their colleagues who were supportive of this research.

Additional information about the study:

This study was conducted by Richard Morrow as his PhD research under the guidance of his co-supervisors Colin R. Dormuth (University of British Columbia) and Barbara Mintzes (University of Sydney) and PhD committee members Garry Gray (University of Victoria) and Michael R. Law (University of British Columbia). Scott Garrison (University of Alberta) also provided critical feedback on the study.

The Principal Investigator of the study was Colin Dormuth, Associate Professor, Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia.