Article Text

Download PDFPDF
Is it ethical to keep interim findings of randomised controlled trials confidential?
  1. F G Miller,
  2. D Wendler
  1. Department of Clinical Bioethics, NIH Clinical Center, Bethseda, MD, USA
  1. Dr F G Miller, Department of Clinical Bioethics, NIH Clinical Center, Building 10, Room 1C118, Bethesda, MD 20892-1156, USA; fmiller{at}


Data monitoring committees often are employed to review interim findings of randomised controlled trials. Interim findings are kept confidential until the data monitoring committee finds that they provide sufficiently compelling evidence regarding efficacy, typically because they have crossed the pre-defined statistical boundaries, or they raise serious concerns about safety. While this practice is vital to maintaining the scientific integrity of controlled trials and thereby ensuring their social value, it has been criticised as unethical. Commentators argue that withholding interim findings from research participants is deceptive, inconsistent with valid informed consent, and a violation of respect for participants’ autonomy. The present article examines these arguments, focusing specifically on confidential data monitoring for efficacy. This practice need not be deceptive provided its use is disclosed to prospective research participants. In addition, confidential data monitoring does not make research participants worse off than they would be in the clinical setting and represents an acceptable limitation on the options available to prospective research participants. Taken together, these considerations suggest confidential data monitoring, subject to adequate safeguards, is ethically acceptable.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • The opinions expressed are those of the authors and do not reflect the position or policy of the National Institutes of Health, the Public Health Service or the Department of Health and Human Services.

  • Competing interests: None.

Other content recommended for you