The importance of tails for clinical expertise

by reestheskin on 07/11/2016

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There is a nice piece by Nassim Nicholas Taleb in Medium. It is from a forward to a book (I think) on physical / strength training. If you have read Taleb you will know this is not too surprising.

You will never get an idea of the strength of a bridge by driving several hundred cars on it, making sure they are all of different colors and makes, which would correspond to representative traffic. No, an engineer would subject it instead to a few multi-ton vehicles. You may not thus map all the risks, as heavy trucks will not show material fatigue, but you can get a solid picture of the overall safety.

Likewise, to train pilots, we do not make them spend time on the tarmac flirting with flight attendants, then switch the autopilot on and start daydreaming about vacations, thinking about mortgages or meditating about corporate airline intrigues — which represent about the bulk of the life of a pilot. We make pilots learn from storms, difficult landings, and intricate situations — again, from the tails.

In one sense he is saying something that is easy to agree with. But if you delve a little deeper, it is not what we always do in medical education.

The structures we create to enable learning in a clinical discipline are not mirrors of what goes on in the real world. Pace the airline example. We shouldn’t expect teaching time to mirror disease prevalence; we don’t spend most of our time in dermatology teaching students about viral warts, or dandruff, or toxic erythema. When you try to recognise objects, you do not just study those particularly objects. Rather, you have to study all the other objects. If you want to be able to ‘call out’ whenever you see a dog, you have to study cats. And chimps, and wolves and so on. This is one of the reasons why just learning about the top ten conditions makes little sense, if acts of recognition are involved. Most things are defined by what they are not. To think in the box, you have to know what is outside the box. This is what makes medical education a hard problem.

There are implications for clinical practice for the expert, too. Everyday practice appears to minimise the role of the statistical tails. Your learning about common condition may be ‘everyday stuff’ requiring little formal study. But for rare conditions, or odd presentations of common conditions, everyday practice, may not be sufficient — simply put, you do not see rare events frequently enough to consolidate and strengthen your memories. Everyday practice rarely provides enough critical mass, you might say. A practical example.

When I was a trainee in Newcastle if we saw an ‘interesting patient’ or a patient in which the diagnosis was unclear, we pressed a buzzer. The buzzer and flashing light went off in all the clinic rooms, the laboratories, the professor’s office and the seminar room. What happened then, resembled the Stepford wives. All descended on the particularly clinic room, as though under some malign influence. There were times when this was quite funny, although some patients might have told this differently.

This simple tool was just an implementation of another one of Rees’s rules: routine clinical practice is not sufficient to consolidate or acquire the skills you need to provide routine clinical practice. This seems like a paradox, but it isn’t. “A sailor gets to know the sea only after he has waded ashore.”  Rather, I always view it as a solution to the forgetting curve that Ebbinghaus described (although I think there may be other justifications)

There is a simple learning point here. The acquisition or maintenance of clinical competence requires much more than seeing patients (and by this, I do not just mean reading research papers). Software, and virtual worlds that we control, might help. But the Rees maxim remains: routine clinical practice is not sufficient to consolidate or acquire the skills you need to provide routine clinical practice