The perils of diagnostic overconfidence

Baruch Fischhoff defined overconfidence as the miscalibration of knowledge or expertise. Writing in a piece titled Heuristics and biases in application, a chapter in the book Heuristics and Biases: The Psychology of Intuitive Judgment‘, he further defined miscalibration as the mismatch between how confident one is, and how confident one should be. According to David Hardman, writing in the book Judgment and Decision Making. Psychological Perspectives, overconfidence is usually the result of a ‘biased search of memory‘ which instils in the practitioner a misleading ‘feeling of certainty‘. Hardman pointed out that overconfidence is more likely to manifest in those who have less knowledge, and this correlation between ignorance and overconfidence is referred to as the Kruger-Dunning effect. Hardman also remarked that men are more likely to manifest overconfidence than women, and he linked this to mens’ desire for status, and their need to display their eminence. Quite counterintuitively, Hardman also noted that experts run the risk of overconfidence when they are hedgehogs – people whose expertise lies in knowing only ‘one big thing‘; in contrast, the risk of overconfidence is minimal in experts who are foxes – those who know ‘many little things‘.

The Fox and the Hedgehog. Laurakgibbs on Flickr.

The major hazard of overconfidence in doctors is the risk of misdiagnosing their patients. Charles Friedman and colleagues, in their study titled Do physicians know when their diagnoses are correct? Implications for decision support and error reduction, explained that ‘clinicians who believe they are correct, or believe they know all they need to know to reach a decision’ are more likely to misdiagnose their patients, and this is because they ‘will be unmotivated to seek additional knowledge’, and they will be ‘unreceptive to any knowledge or suggestions a decision support system presents to them’. In another paper titled Are clinicians correct when they believe they are correct? Implications for medical decision support, Friedman and colleagues further argued that overconfident doctors, those ‘who believe they are correct when in fact they are not’, are doctors that are ‘prone to medical errors‘.

Such Shame. Royal Constantine on Flickr.

Another way that overconfidence impairs the making of correct diagnoses is by increasing the practitioner’s vulnerability to other cognitive biases. This point was made by Eta Berner and Mark Graber in their paper titled Overconfidence as a cause of diagnostic error in medicine. Berner and Graber observed that it is in cases where doctors are certain of their diagnosis that they are most likely to make diagnostic cognitive errors. They further pointed out that doctors are more likely to be overconfident in their diagnoses when ‘the problem appears to be routine and resembles similar cases that the clinician has seen in the past’. They added that the feeling of certainty in such situations leads to overconfidence because it hinders the doctor from experiencing ‘metacognitive angst‘- the mental discomfort that makes doctors cautious when approaching the diagnosis of ‘more challenging cases‘.

Thinking. Flik on Flickr.

Apart from the feeling of certainty, other factors that Berner and Graber identified as promoting overconfidence are:

    • Physicians’ belief that ‘they personally are unlikely to make a mistake’.
    • Physicians’ assumption that ‘the likelihood of error is less than it really is’
    • Physicians’ routine disregard for guidelines and decision support tools.
    • Physicians’ failure to seek and learn from feedback from autopsies and other forms of ‘independent information on their diagnostic accuracy‘.
Computer-Phone-Tablet-Technology. Blue Coat Photos on Flickr.

In the next blog post, we will take a look at the diagnostic failure that arises from over-diagnosis.

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