── ── Cognitive bias
Dunning-Kruger Effect
The Dunning-Kruger effect is the systematic self-assessment asymmetry demonstrated by Kruger & Dunning (1999): bottom-quartile performers overestimate rank by ~50 percentile points; top-quartile performers underestimate by ~5 points. Mechanism: the cognitive skills needed to perform a task are the same ones needed to evaluate performance — so novices lack the metacognition to see their own gap. The corrective is external…
Run Dunning-Kruger Effect on a real problem
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How it works
Step 1 — State the claim: Domain · verbatim claim · self-assessed percentile · basis for assessment · stakes.
Step 2 — Test metacognitive prerequisite: Can the person evaluate others' performance in this domain? Have they received external feedback? Can they articulate what failure looks like?
Step 3 — Get external data: Objective metrics · blind peer comparison · expert evaluation · track record · calibration test (predict score → take test → compare).
When to use it
- someone says 'how hard could it be' about an unfamiliar domain
- a novice dismisses expert opinion or says 'I could do that'
- someone's self-assessed confidence seems disconnected from their actual track record
- a hiring or promotion decision is driven by self-presentation
- feedback loops are absent and someone is operating on gut confidence alone
When not to use it
the person is a known expert with an established external track record; the confidence claim is in a domain with tight, recent feedback loops that already calibrate performance.
Worked example
Cost Forecasts in Public Works Projects (1910–1998)
The Dunning-Kruger structure — confident self-assessment uncorrected by absent feedback — operates at institutional scale in infrastructure planning. Flyvbjerg, Holm, and Buhl (2002) assembled the first statistically significant sample of large transportation projects and compared forecast costs against actual costs. The result is the effect written in concrete and steel.
Install this skill (free, MIT)
npx skills add deciqAI/knowledge-skillsUseful? Star the repo — stars help other builders find it.
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