Examining Explanations of a Market Anomaly: Preferences or Perceptions?

Abstract

This paper compiles and summarizes the theoretical literature on the favorite-longshot bias, an anomaly that has been found in sports betting markets for over half a century. Explanations of this anomaly can be broken down into two broad categories, those involving preferences and those involving perceptions. We propose a novel test of these two classes of models that allows us to discriminate between them without parametric assumptions. We execute these tests on a new dataset, which is an order of magnitude larger than any used in previous studies, and conclude that the perceptions model, in which bettors overestimate the chances of small probability events, provides a better fit to the data.