RCTs and the kudos of stacking shelves

by reestheskin on 31/07/2017

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Many many years ago I wrote a few papers about — amongst other things — the statistical naivety of the EBM gang. I enjoyed writing them but I doubt they changed things very much. EBM as Bruce Charlton pointed out many years ago has many of the characteristic of a cult (or was it a Zombie? — you cannot kill it because it is already dead). Anyway one of the reasons I disliked a lot of EBM advocates was because I think they do not understand what RCTs are, and of course they are often indifferent to science. Now, in one sense, these two topics are not linked. Science is meant to be about producing broad ranging theories that both predict how the world works and explain what goes on. Sure, there may be lots of detail on the way, but that is why our understanding of DNA and genetics today is so different from that of 30 years ago.

By contrast RCTs are usually a form of A/B testing. Vital, in many instances, but an activity that is often a terminal side road rather than a crossroads on the path to understanding how the world works. That is not to say they are not important, nor worthy of serious intellectual endeavour. But the latter activity is for those who are capable of thinking hard about statistics and design. Instead the current academic space makes running or enrolling people in RCT some sort of intellectual activity : it isn’t, rather it is a part of professional practice, just as seeing patients is. Companies used to do it all themselves many decades ago, and they didn’t expect to get financial rewards from the RAE/REF for this sort of thing. There are optimal ways to stack shelves that maths geeks get excited about, but those who do the stacking do not share in the kudos — as in the cudos [1] — of discovery.

Anyway, this is by way of highlighting a post I came to by Frank Harrell, with title:

Randomized Clinical Trials Do Not Mimic Clinical Practice, Thank Goodness

Harrell is the author of one of those classic books…. . But I think the post speaks to something basic. RCT are not facsimiles of clinical practice, but some sort of bioassay to guide what might go on in the clinic. Metaphors if you will, but acts of persuasion not brittle mandates. This all leaves aside worthy debates on the corruption that has overtaken many areas of clinical measurement, but others can speak better to that than me.

[1] I really couldn’t resist.