Explaining the Favorite-Longshot Bias: Is It Risk-Love or Misperceptions?

Working Paper: CEPR ID: DP7801

Authors: Erik Snowberg; Justin Wolfers

Abstract: The favorite-longshot bias describes the longstanding empirical regularity that betting odds provide biased estimates of the probability of a horse winning?longshots are overbet, while favorites are underbet. Neoclassical explanations of this phenomenon focus on rational gamblers who overbet longshots due to risk-love. The competing behavioral explanations emphasize the role of misperceptions of probabilities. We provide novel empirical tests that can discriminate between these competing theories by assessing whether the models that explain gamblers? choices in one part of their choice set (betting to win) can also rationalize decisions over a wider choice set, including compound bets in the exacta, quinella or trifecta pools. Using a new, large-scale dataset ideally suited to implement these tests we find evidence in favor of the view that misperceptions of probability drive the favorite-longshot bias, as suggested by Prospect Theory.

Keywords: compound lotteries; favorite-longshot bias; pricing under risk; probability weighting

JEL Codes: D03; D49; G12; L83


Causal Claims Network Graph

Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.


Causal Claims

CauseEffect
bettors' perceived probabilities (L83)actual odds (C46)
bettors' perceived probabilities (L83)returns on bets (L83)
actual odds (C46)returns on bets (L83)
misperceptions of probability (D80)favorite-longshot bias (G41)
risklove (D81)favorite-longshot bias (G41)

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