The GMC emphasises that medical students must recognise the limits of their competence and ask for help and advice when necessary - a principle echoed in guidance for registered doctors ('Good medical practice', paragraph 2).
In today's fast-paced healthcare environment, most care is unsupervised, leaving individual practitioners to decide if they're capable of performing a task.
The problem? We're not very good at estimating our own ability.
When investigating a doctor's actions, the most important factor in determining the outcome is their understanding of how their actions impacted the patient - a concept the GMC calls 'insight'.
However, the Dunning-Kruger effect can limit this self-awareness, sometimes with devastating consequences for both doctors and patients. On the other hand, embracing our fallibility can help both students and doctors to become truly exceptional clinicians.
The Dunning-Kruger effect
Dunning and Kruger did a number of studies on undergraduates at Cornell University, plotting students' self-rated competence against objective measurements of their ability.
Their findings consistently showed that:
- high performers tend to underestimate their ability
- low performers tend to overestimate their ability.
Most worrying of all, the gap between perceived competence and actual ability grows wider as objective ability decreases. In other words, the worst performers are often the least self-aware.
Dunning and Kruger hypothesised that the skills needed to be competent in a task are the same skills needed to evaluate one's competence. To test this, they asked both high and low performers to mark papers by other students and estimate their ranking within the group.
They found that poor performers not only evaluated their peers inaccurately but also further overestimated their own abilities. It is thought this likely occurred because they couldn't recognise correct answers when reviewing others' work. Lacking this awareness, they assumed they had performed well.
Many studies have shown that people in a diverse range of situations and professions tend to evaluate their ability as 'above average', even when they objectively fall below it.
In their studies, Dunning and Kruger found that:
- those in the bottom 25% overestimated their abilities, rating themselves on the 66th percentile of their peer group
- conversely, those in the top 25% underestimated their abilities, only placing themselves in the 70-75th percentile range.
The Dunning-Kruger (DK) effect is an example of an unconscious bias - it operates outside our awareness but affects the decisions we make, including clinical ones.
The gaps in our knowledge act as blind spots, reinforced by other biases like confirmation bias. This is where we unknowingly focus only on evidence that supports, or confirms, our conclusion, while ignoring all the evidence to the contrary. If the only feedback comes from others with similar blind spots, it perpetuates errors and prevents further learning.
How does this impact medical training?
The DK effect has been demonstrated in many professions, including medicine, in both students and doctors (references 36, 37, 38 and 39 here). Studies in surgery, psychiatry and anaesthetics have looked at decision-making and the ability to perform clinical procedures.
Adult learning is self-directed. This means that in order to progress, students should know what they need to work on. An overestimation of ability can prevent students from identifying the most useful areas for study.
It's important to study with people who don't share the same blind spots in knowledge or skill. The DK effect isn't dependent on how much time you spend studying. Students often reinforce what they already know instead of addressing the weaknesses they didn't know they have.
The DK effect applies broadly - across many, if not all, skills. It's relevant to mastering advanced communication techniques and to learning technical procedures. Every time you learn a new skill, you'll likely go through a phase of overestimating your abilities, completely unaware of what you don't know that you don't know.
With proper feedback, you'll gain a clearer understanding of your limits. At that point, remember that true experts underestimate their ability - probably because they're keenly aware of the vastness of what they still don't know.
Some skills take decades to master, or might only become important once you're a consultant or a partner. And some clinical presentations are so rare you may only see them once in a lifetime. Regardless of your experience level, you might still find yourself overestimating your abilities in certain areas.
The DK effect is universal, affecting everyone in some capacity.
It even happens to patients
Some patients might consider themselves well informed, and many genuinely are experts in their own condition.
However, others fall into the Dunning-Kruger trap, overestimating their knowledge. This can be compounded by confirmation bias, where patients seek reassurance only from those who share their views, possibly on social media.
As a clinician, you can help by building a rapport and providing accurate, factual information to guide them towards a clearer understanding of their condition.
What to do about it
In an attempt to improve the accuracy of the self-ratings, Dunning and Kruger provided participants with a financial incentive for accuracy in one study, and told students in another that they would have to explain their decision. Paradoxically, these interventions amplified the effect, suggesting that participants' initial estimates were modest.
The original paper by Dunning and Kruger postulated that the way to overcome this lack of self-awareness was to gain competence. They tested this by providing a course on logical reasoning and compared self-assessments before and after, alongside objective test scores. The gap narrowed dramatically, and students more accurately rated both their earlier and current performance.
In clinical practice, achieving competence requires honest feedback from experts. At times this will be unsettling and might even feel unfair, because the criticism will be so different to the reassurance you had from your peers. Sometimes, a blind spot in your knowledge only becomes apparent through a clinical incident or complaint. While unpleasant, these are valuable learning experiences.
When students disregard expert feedback and cling to their own assessments, medical schools are likely to say they lack insight and might deem them not fit to practice.
Conversely, students who reflect on feedback and acknowledge their gaps can demonstrate professionalism and achieve significant growth.
This page was correct at publication on 17/02/2025. Any guidance is intended as general guidance for members only. If you are a member and need specific advice relating to your own circumstances, please contact one of our advisers.
by Dr Oliver Lord MDU medico-legal adviser
Oliver is part of a specialist advisory team that assists MDU members with disciplinary investigations and has an interest in doctors’ wellbeing. Before joining the MDU in 2013, Oliver was a consultant psychiatrist in a crisis resolution team. He provides regular talks and courses to members on medico-legal issues, conflict resolution and unconscious bias.