Thinking, Fast and Slow · Daniel Kahneman

The overconfidence effect examples

Curated by · reviewed 2026-06-01

The overconfidence effect is being surer than we are right — our confidence routinely outruns our accuracy, especially when we know little about something. Examples:

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5 examples of the overconfidence effect

  1. '90% sure' and often wrong

    When people say they're 90% certain, they tend to be correct far less than 90% of the time.

  2. Project timelines

    Teams confidently promise dates they then blow past — confidence about the future outpaces reality (see the planning fallacy).

  3. Above-average drivers

    Most people rate themselves better-than-average drivers, which simply can't be true for most of them.

  4. New investors

    A couple of early wins breed certainty, and certainty breeds bigger, riskier bets.

  5. Exam confidence

    The students who walk out feeling most sure aren't always the ones who scored highest.

How to spot it in yourself

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