“No problem in judgment and decision making is more prevalent and more potentially catastrophic than overconfidence”. – Plous (1993)

The overconfidence effect is a well-established bias in which a person’s subjective confidence in his or her judgments is reliably greater than the objective accuracy of those judgments, especially when confidence is relatively high.^[1] For example, in some quizzes, people rate their answers as “99% certain” but are wrong 40% of the time.^{[citation needed]} Overconfidence is one example of a miscalibration of subjective probabilities. Throughout the research literature, overconfidence has been defined in three distinct ways: (1) overestimation of one’s actual performance, (2) overplacement of one’s performance relative to others, and (3) the excessive certainty regarding the accuracy of one’s beliefs − called overprecision.^[2]