The Dunning-Kruger effect is subtler than you think

The Dunning-Kruger effect — named after David Dunning and Justin Kruger's 1999 Cornell study — is typically summarised as 'incompetent people think they're experts'. The actual finding is more nuanced: novices tend to overestimate their performance, while genuine experts tend to slightly underestimate it. Crucially, the gap exists at all competence levels — it's not just a flaw of the unskilled. A 2020 reanalysis by Gilles Gignac suggested some of the original finding may be a statistical artefact, but the core insight — that self-assessment and actual ability are often poorly correlated — is robust.

Source: Dunning & Kruger, Journal of Personality and Social Psychology (1999)