Intended for healthcare professionals

Opinion Acute Perspective

David Oliver: Covid-19 and the Dunning-Kruger effect

BMJ 2022; 378 doi: (Published 13 July 2022) Cite this as: BMJ 2022;378:o1701
  1. David Oliver, consultant in geriatrics and acute general medicine
  1. Berkshire
  1. davidoliver372{at}
    Follow David on Twitter @mancunianmedic

In 1999 two social psychologists, Dunning and Kruger, described the phenomenon of “illusory superiority”: a cognitive bias in which people who are unskilled, yet unaware of their lack of competence, have an inflated self-assessment of their own abilities and a lack of insight to recognise their incompetence. Dunning and Kruger also described a cognitive bias in which people who do excel and are highly expert tend to underestimate their knowledge and performance by overestimating these in others, and they fail to recognise their own exceptional abilities.12

It seems that this cognitive bias has played a part in the public narrative and debate around our pandemic response. The covid era has seen plenty of people with no relevant background or experience steaming confidently into the media arena and often arguing with professional experts about their specific disciplines and daily work, often seemingly unaware of just how much they don’t know.

I’m not talking here about legitimate and multifaceted debates about the evidence base around covid prevention, transmission, and management or public policy responses. Experts debating and contesting empirical evidence and hence the best policy approaches are not usually showing illusory superiority. However, some of the most confident debaters are often way outside the mainstream of expertise in the field they’re commenting on or seeking to influence, even if they’re scientifically literate and skilled in analysing (and sometimes very selectively presenting) data to bolster particular lines of argument.

For me, where the more genuine Dunning-Kruger effect has been most apparent has been on social media—including dedicated sites, groups, or hashtags—usually dominated by people who oppose covid health protection measures. I worry that all of this exemplifies a wider societal breakdown of trust in experts and trained professionals—not least those who are telling us things we don’t want to hear and supporting public health measures in our lives that we don’t want to see.

Combating the Dunning-Kruger effect requires a willingness to reflect, to challenge oneself or be challenged, to get objective feedback, and to improve our knowledge or skill and learn from people with more expertise. But I guess that, psychologically, that feels like a less safe space.

Meanwhile, perhaps those individuals who are highly competent and credible among their expert peers should go out of their way to communicate with the rest of us in plain language and accessible formats, to enhance our understanding and help avoid the normalisation of false belief systems that are over-confidently asserted by inexpert people.