The Probability of Winning and the Effect of Home-Field Advantage: The Case of Major League Baseball‪.‬

ABSTRACT This paper examines the factors that affect the probability of a major league baseball team winning a game. The basic hypotheses of the study are that home teams are more likely to win a game than visiting teams, that teams that travel to arrive at a game are less likely to win the game than teams that don't, and that teams having a strong batting performance are more likely to win a game than teams having a weak batting performance. To examine these issues, we estimate five logit regressions from data for all 2,428 regular season games played during the 2004 season. We find that while the strength of a team's batting performance does affect its probability of winning, travel does not affect the likelihood of either the home team or visiting team winning a game. The major finding of the paper, however, is that contrary to the commonly held belief that a home-field advantage exists in major league baseball games, home teams only have an advantage over visiting teams in very close games. In games that are won by more than one run, the likelihood of winning is roughly equal for home teams and visiting teams.