Dunning–Kruger Effect
The less skilled we are at something, the more we tend to overrate our skill at it.
Also known as: Confidence-competence gap
intermediate Attributed to David Dunning & Justin Kruger · Social psychology
The Dunning–Kruger effect describes how people with low competence in a domain often overestimate their ability, because the very knowledge needed to do the task well is also what's needed to recognise how badly one is doing it. Skill and the ability to judge that skill are linked.
What it is
David Dunning and Justin Kruger found that low performers not only did poorly but rated themselves far higher than their results justified. The insight is that competence is often required to assess competence: if you don't know the rules of good grammar, you can't see the grammar errors you're making, so you feel fine.
There's a flip side. Genuine experts sometimes underrate themselves — partly because they assume tasks that are easy for them are easy for everyone. So the gap between confidence and competence is largest at the bottom and can invert at the top.
The effect is frequently exaggerated online into "idiots think they're geniuses," which overstates it. The careful claim is narrower: self-assessment is unreliable, and it's least reliable exactly where you know the least.
Worked example
Someone watches a few videos on investing and feels ready to beat the market — the topic seems straightforward because they can't yet see what they don't know. A seasoned investor, aware of the countless ways to be wrong, hedges and expresses uncertainty. To an outsider the novice sounds more confident than the expert. Confidence, here, is running inverse to actual competence.
How to counter it
The effect is often misapplied as an insult ("you're just Dunning–Kruger"), which is both rude and usually wrong about the research. As a bias to guard against in yourself, the trap is trusting your self-rating in an area where you're a beginner. The remedy is external feedback and objective measures, not more introspection.
How to apply it
- In a new domain, treat your own confidence as weak evidence of skill.
- Seek objective feedback and measurable results, not self-assessment.
- When you feel a topic is "obvious," ask what an expert would say you're missing.
- Notice that real experts often sound less certain — that's a feature, not a flaw.