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In 1977, Zelen proposed a new design for clinical trials with the aim of increasing recruitment by avoiding some of the problems associated with obtaining informed consent. These 'randomised consent' designs have proved controversial, and have not often been used. This paper explains the statistical aspects of single and double randomised consent designs and reviews some of the ethical issues. All identified published cancer treatment trials using a randomised consent design are considered in some detail. Reasons for and against the use of these designs are summarised.


Journal article


Eur j cancer

Publication Date





1934 - 1944


Biomedical and Behavioral Research, Ethics, Medical, Humans, Informed Consent, Neoplasms, Randomized Controlled Trials as Topic, Research Design