Medical expertise

It has been plausibly argued by the psychologist, Daniel Kahneman, in his brilliant new book on human cognition, „Thinking, fast and slow“,  that true expertise depends on two factors, namely the length of the expert’s personal experience and the speed and quality of the feedback.

That experience is necessary has been widely accepted for a very long time, but what has not been sufficiently recognized is the importance of the nature of the feedback. The speed of the feedback is crucial because the more rapid it is, the easier and the more effective the learning becomes. In this respect aircraft pilots who get immediate feedback about how good, say, their landing is, can develop their landing technique much more quickly than the captains of large ocean-going ships who have to spend much longer learning how to dock because of the relatively long delay between their actions and the observable outcomes of those actions. Clearly the feedback has to be reliable, and we can actually end up learning how to make mistakes if the feedback is not.

When we apply these basic principles to medical expertise we get some surprising results. Of the various medical specialties, it is the anaesthetists who get the fastest and most reliable feedback and thus have the opportunity to acquire genuine expertise. At the opposite end of the spectrum, pathologists get virtually no feedback. They pronounce their verdict on the most probable cause of death and that is nearly always the final word on the matter. They never find out whether they were right or wrong, apart from the very rare circumstances in which their findings are contested in court and a second opinion is then sought. When they examine biopsy tissue taken from a living patient, they seldom get information about the further course of that patient’s illness. Radiologists evaluate the images taken of parts of the bodies of living patients, but they too rarely discover what subsequently happens to these patients. Even if they are administering radiotherapy they see the patients relatively briefly, and only during the duration of the course of treatment. Experienced radiologists who examined the same chest X-rays on separate occasions changed their minds about the findings 20% of the time.

The expertise of other medical specialists lies somewhere between these two extremes. Surgeons will see the immediate effects of their operations, but, as a rule, little beyond that. Psychotherapists get very good feedback during individual sessions and thus become experts in anticipating the immediate effects of what they say to their patients and how those patients might react in response – during the sessions. They also see the intermediate effects of therapy, as long as that therapy continues. But once therapy has finished they rarely learn anything further about their patients and how they are faring. General practitioners and community psychiatrists who remain in their posts for long enough will have the opportunity to follow up their patients for years, and thus to discover what the longer-term effects of their interventions might be. Complementary therapists are also able to follow up their patients for lengthy periods, but have the added advantage over GPs and psychiatrists that they spend much longer in individual consultations with their patients and not only get to know them better but also get much better feedback.

Nowadays much more emphasis is placed on continuous professional development, or CPD, which will become mandatory in the UK in all medical specialities. But if the aim of CPD is to ensure that medical specialists maintain and enhance their expertise for the good of their patients, then ways of improving the feedback that those specialists receive, or in some cases, do not receive need to be urgently considered and implemented.

Paul Crichton
2 January 2012

For more information on this topic, see:

Daniel Kahneman, Thinking, Fast and Slow (2011), Penguin Books, London