This paper raises the important philosophical distinction between evidence and truth. The point here seems to be that statistical means of discerning the truth about the systems in point cannot be relied upon to access the underlying truth until there are sufficient events for a true picture of the underlying reality to be formed. Before this sufficient accretion of data there is a great deal of noise in the signal.

The moral problem is who, within the trial community, is obliged to guard against this type of misperception impacting adversely upon the scientific evidence base and clinical care?

I would argue that it should not fall to those who might face a conflict of interests in reaching such a decision. Thus researchers, research funding bodies and journals are perhaps not best placed to attend to this problem. The authors rightly criticise guideline committees for seeking to offer advice when the underlying evidence base, whilst in existence, is insufficient to permit the underlying truth to be accurately discerned. (1)

One option might be to require a more powerful role for research ethics committees in scrutinising the scientific validity of the trial stopping rules on the basis that this is actually an ethical issue arising from the scientific design.

(1) See Mohindra RK. A case of insufficient evidence equipoise: the NICE guidance on antibiotic prophylaxis for the prevention of infective endocarditis. J Med Ethics 2010;36:567-570 doi:10.1136/jme.2010.036848

Competing interests: I am an expert member of a local research ethics committee