Nevertheless, although most published RCTs probably estimate treatment effects reliably, allocation breaches seem to be more than rare. Whilst the stories frequently revealed ingenious efforts, they also frequently reflected naive, questionable judgment. Assignment manipulations by investigators manifest larger underlying conflicts. Trialists theoretically understand the need for unbiased research, but remaining dispassionate may be too difficult once the trial starts. 16 Those who fail to comply with an assignment scheme do not necessarily have sinister motives.
Many subversions reflect human curiosity rather than scientific malevolence.
For those involved in implementing a trial that has not incorporated proper procedures for sequence generation and allocation concealment, the challenge of deciphering the allocation scheme may become irresistible. Whatever the motivation, however, the effects are the same if the introduction of bias invalidates the trial comparisons. We must all acknowledge the human elements of this important scientific process and realise that, given the opportunity, researchers sometimes subvert randomisation. Fortunately, subversions of randomisation can generally be prevented with assiduous attention to design and implementation. Trial designers and trialists need to embrace the rationale and ethos of randomisation.