Overconfidence Bias

topic

Overconfidence bias is the systematic tendency to overestimate the accuracy of one's own knowledge, predictions, and judgments — documented across domains from financial forecasting to medical diagnosis to everyday planning — producing calibration gaps where people expressing '90% confidence' are correct only 70% of the time, and where the subjective feeling of certainty bears little relationship to the actual probability of being correct.

Role

Overconfidence is not merely a statistical curiosity — it is a primary driver of catastrophic individual and collective failures. The majority of startup failures, investment losses, failed projects, and misjudged risks involve decision-makers who were subjectively confident that their assessment was correct. Worse, research shows that competence and confidence are poorly correlated: people who are genuinely skilled in a domain often know enough to be aware of the complexity and uncertainty involved (producing calibrated confidence), while people with limited knowledge in the same domain lack the framework to perceive those complexities and experience unwarranted certainty. This is the Dunning-Kruger effect — and it means the most confident voice in a room is often not the most informed one.

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