We analyze data from 52 online in-game sports betting markets (where betting is allowed continuously throughout a game), including 34 markets based on soccer (European football) games from the 2002 World Cup, and 18 basketball games from the 2002 USA National Basketball Association (NBA) championship. We show that prices on average approach the correct outcome over time, and the price dynamics in the markets are closely coupled with game events, agreeing with efficient market assumptions. We also examine qualitative distinctions between the two types of games. Categories and Subject Descriptors J.4 [Computer Applications]: Social and Behavioral Sciences—Economics; G.3 [Mathematics of Computing]: Probability and Statistics General Terms Economics, Measurement Keywords Information incorporation, economic efficiency, efficient markets hypothesis, in-game sports betting, market reaction, soccer, logarithmic score, entropy.
Sandip Debnath, David M. Pennock, C. Lee Giles, St