Clinical Research Transparency and Lack Thereof: Does Publishing Lead to Credibility?

Clinical Trial TrialsiteN

Researchers from Stanford, Harvard, London School of Economics and University of Ioannina School of Health Sciences came together to produce an analysis of the nature of and risks associated with unpublished clinical research.

Large clinical trials that go unreported (or underreported) challenge the ultimate legitimacy of available, published evidence and are detriment to the scientific process based on this streamlined study published in the Annals of Internal Medicine.

The Study Method

The researchers utilized government-sponsored website to identify the 500 largest, unpublished, pre registered randomized clinical trials (RCT) ranging from June 1, 2007 to June 1, 2012. They culled those studies that remained unpublished for more than 46 months after completion.  The team excluded nonrandomized, cluster-randomized, and non-preregistered trials.  Moreover, the multi-national and multi-institution research team monitored the studies for subsequent published results.

The research team utilized only one registry. It is not comprehensive nor complete by any means. It represents a slice of reality; an analysis of a segment of important information that leads to a range of further questions.

The Findings

60 of the 146 large RCTs without main publications listed or results posted by April 2016 were actually published by that period. Out of the 84 RCTs unreported by April 2016, 17% (14) were published by January 2019.

The research team found many large trials went unreported.  For example, they uncovered 5 lengthy unreported antidepressant studies. Moreover, the biggest meta-analysis on the identical topic uncovered only 32 trials of equal size. The research team concluded that big clinical trials that stay unreported for 4 or more years post completion will typically never be published.  This results in the loss of evidence for almost 90,000 study participants.


The authors say the clinical research credibility could be threatened by the significant lack of published material. Moreover, in an age with considerable lack of trust in biopharmaceutical companies more transparency can possibly lead to greater trust and improved brands.

Research Team

University of Ioannina School of Health Sciences, Ioannina Greece

Stanford University, Stanford, CA

Brigham and Women’s Hospital and Harvard Medical School, Boston MA

London School of Economics and Political Science, London, UK