Intended for healthcare professionals


Pursuit of truly independent data monitoring committees in research

BMJ 2016; 353 doi: (Published 12 May 2016) Cite this as: BMJ 2016;353:i2309
  1. Louise Marston, senior research statistician1,
  2. David R McKenzie, senior director2,
  3. Nick Freemantle, professor of clinical epidemiology and biostatistics1
  1. 1Department of Primary Care and Population Health and Priment Clinical Trials Unit, UCL, London NW3 2PF, UK
  2. 2Covance, Princeton, NJ, USA
  1. Correspondence to: L Marston l.marston{at}

Here the drug industry leads the way, with academia coming a poor second

Independent data monitoring committees aim to protect the interests of trial participants, and their duty of care towards participants should not be affected by conflicting interests. Many agencies overseeing medical research have drawn up guidance on the topic. The International Conference on Harmonisation states: “All staff involved in the conduct of the trial should remain blind to the results of [interim] analyses, because of the possibility that their attitudes to the trial will be modified and cause changes in the characteristics of patients to be recruited or biases in treatment comparisons.”1 2

The US Food and Drug Administration and the European Medicines Agency provide similar regulatory guidance.3 4 Neither requires the statistician performing the interim analyses to be independent or different from those involved in managing the trial and performing the final analyses. However, the FDA states: “The integrity of the trial may be best protected when the statisticians preparing unblinded data for the DMC [data monitoring committee] are external to the sponsor and uninvolved in discussions regarding potential changes in trial design …

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