# Why Half of Our Decisions Turn Out to Be Wrong: Overconfidence Bias

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- Last updated: 2026-09-10
- Page title: Why Half of Our Decisions Turn Out to Be Wrong: Overconfidence Bias | Assoc. Prof. Dr. Alişan Burak Yaşar

> Half of managerial decisions are either never implemented or remain incomplete two years after they are made. That is the finding from 356 decisions collec

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# Why Half of Our Decisions Turn Out to Be Wrong: Overconfidence Bias

September 10, 2026Recent Articles

Half of managerial decisions are either never implemented or remain incomplete two years after they are made. That is the finding from 356 decisions collected during a twenty-year research program in the United States and Canada. 📊

This study is not called "overconfidence bias," but its finding points directly to it: the confidence felt when making a decision is not the same as the likelihood that the decision will later prove correct. In the psychological literature, this is known as the confidence–accuracy gap.

A meta-analysis examining clinicians' diagnostic judgments found a very weak relationship between confidence and accuracy (r=0.15). A broader meta-analysis combining different decision-making tasks points to a similar picture (R=0.22); the relationship is generally weak. One reason for this is the "bias blind spot": it is easy to see bias in someone else's thinking, but much harder to recognize the same bias in our own decisions. 🧠

Two practical steps: before making your decision, write down a few reasons why it might turn out to be wrong; this is one of the few methods shown to reduce overconfidence. And rather than imposing the decision on your own, consult those involved; this significantly increases the rate of implementation.

This content does not constitute diagnostic or treatment advice.

References:
Nutt (1999), Academy of Management Executive
Koriat, Lichtenstein ve Fischhoff (1980), Journal of Experimental Psychology
Miller, Spengler ve Spengler (2015), Journal of Counseling Psychology
Jin, Verhaeghen ve Rahnev (2022), Psychonomic Bulletin & Review
Pronin, Lin ve Ross (2002), Personality and Social Psychology Bulletin

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