Streaky Hitting in Baseball

Abstract

The streaky hitting patterns of all regular baseball players during the 2005 season are explored. Patterns of hits/outs, home runs and strikeouts are considered using different measures of streakiness. An adjustment method is proposed that helps in understanding the size of a streakiness measure given the player's ability and number of hitting opportunities. An exchangeable model is used to estimate the hitting abilities of all players and this model is used to understand the pattern of streakiness of all players in the 2005 season. This exchangeable model that assumes that all players are consistent with constant probabilities of success appears to explain much of the observed streaky behavior. But there are some players that appear to exhibit more streakiness than one would predict from the model.