“Registered Clinical Trials Make Positive Findings Vanish”


A study in PLoS One shows that the number of National Heart Lung, and Blood Institute (NHLBI) funded drug trials reporting positive results declined precipitously after the implementation of the clinicaltrials.gov registry, which requires researchers to record their trial methods and outcome measures before collecting data.  Of the 55 studies examined, 57% percent of those published before the implementation of clinicaltrials.gov in 2000 yielded a positive result.  After 2000, only eight percent of trials claimed a significant benefit to the intervention examined.

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Kaplan, R. M., & Irvin, V. L. (2015). Likelihood of Null Effects of Large NHLBI Clinical Trials Has Increased over Time. PloS one, 10(8), e0132382. (Full Text)


  1. This was really a weak study. If the same type of trials were carried out pre-2000 and post-2000, the paper’s conclusions would be justified.

    But the pre-2000 trials were mostly seminal studies of new interventions such as statins, the efficacy of which has been independently confirmed in multiple other trials. In contrast, over a third of the post-2000 trials were of HRT, and a majority of the remainder were of incremental strategies such as “2 drugs instead of 1”.

    There might actually have been some shifting of trial endpoints in the pre-2000 period, but if so, this study doesn’t demonstrate it. The vast majority of the pre-2000 trials would have given positive results, and the vast majority of the post-2000 trials would have given negative results, whether the endpoints were pre-specified or not

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  2. It is just a bunch of manufactured words to make the “general public” who they consistently “look down upon” as less worthy than themselves; because of all their alleged intelligence and education think they are doing something important and thinking about it. This is not really a fact; but a gut opinion of mine: Statistics kills; even bad statistics that no one can really understand; because it is not made to be understood? Could it be that those who generated those numbers and statistics don’t understand them, either? It is just a thought on a Late August night. Thank you.

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    • “Could it be that those who generated those numbers and statistics don’t understand them, either?”
      Not only could – it’s very often the case. The knowledge of statistics in people who conduct these studies is very low and I can tell you that as an insider.

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