An Investigation of Strategies in Baseball

The advisability of a particular strategy must be judged not only in terms of the situation on the bases and the number of men out, but also with regard to the inning and the score. Two sets of data taken from a large number of major league games are used to give (1) the dependence of the probability of winning the game on the score and inning, and (2) the distribution of runs scored between the arrival of a new batter at the plate in each of twenty-four situations and the end of the half-inning. The first shows that the runs adding most to the probability of winning are the one tying the score and the one putting the batting team one ahead. All other runs are slightly less valuable early in the game, and become increasingly less valuable as the game proceeds. By combining the two sets of data, the situations are determined in which an intentional base on balls, a double play allowing a run to score, a sacrifice, and an attempted steal are advisable strategies, if average players are concerned. An index of batting effectiveness based on the contribution to run production in average situations is developed.