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Paper 2: Are Distinctive Ethical Principles Required for Cluster Randomised Controlled Trials?

Paper by J L Hutton

Cluster randomised trials, ethics, medical research, health services research.


To appear in Statistics in Medicine.


Cluster randomised trials are increasingly used in research into health care and healthservices. Ethics of individual patient randomised trials have been elucidated in a number ofdifferent codes, but less attention has been given to the ethical issues raised by cluster randomisedtrials. I assess the challenges raised by cluster randomised controlled trials by consideringthree questions:

  1. What are the essential elements of ethical medical research, particularly experiments on people?
  2. What are the features which distinguish cluster randomised controlled trials from ordinary RCTs?
  3. Do the distinctive features of cluster randomised trials entail new ethical principles, or careful application of existing principles?

I conclude that cluster randomised controlled trials raise new issues on the nature andpractice of informed consent, because of the levels at which consent can be sought, and forwhich it can be sought. In addition, careful consideration of the principlesrelating to the quality of the scientific design and analysis, balance of risk and benefit, liberty to leave atrial, early stopping of a trial and the power to exclude people from potential benefits is required.

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Jane L Hutton
28 June 2000