Measuring overconfidence: An item response theory approach

Overconfidence refers to the overestimation of one’s own abilities, and it is generally measured as the difference between the expected (or subjective) and actual results in a task. We propose an alternative way to measure overconfidence using psychometric tools. Participants are asked to answer a Multiple Choice Test (MCT), and the data obtained are used to fit an Item Response Theory (IRT) model which allows us to take into account test features such as the degree of difficulty and the discrimination power of each item in the test. These features, which are not even considered in the classical measures of overconfidence, open up the opportunity to provide a more reliable measure of overconfidence.