OK, this is a proposed statistic for the stat-heads on this site to consider. The purpose of playing a baseball game is to win it. My proposal is to quantify how much the outcome of a batter's plate appearance affects his team's chance of winning the game. That is the most important measure of a batter's performance. Batting average, OPS, all else, is secondary. I am aware that win probabilities have been researched although I don't have the time, ability or resources to investigate that myself. For those reading this who aren't aware of win probability, or WinProb as I think it's often called, it's the likelihood of a team winning a game starting from a particular point in the game. The parameters taken into account are the inning and number of outs, number and position of baserunners, run differential and whether the team is visiting or home. The win probability is calculated from the percentage of times a major league team that was at that particular point has gone on to win a game. (As you can imagine, collecting these data is an extremely tedious and time-intensive process.) I'd call this proposed stat ∆WinProb. (Delta is the symbol used in statistics for "change in". It can be positive or negative). For example, in the bottom of the ninth inning with two outs, the bases empty and the score tied a base on balls has a much lower ∆WinProb than a home run. In the bottom of the ninth with two outs, the bases loaded and the score tied a base on balls is equal in value to a home run. There are at least two variations of this to consider. One is the cumulative ∆WinProb, and another is ∆WinProb per plate appearance. There are many other factors to consider. One example: how should a batter be credited when an error occurs? I think the batter should receive some sort of partial credit for putting the ball in play but probably not as much as for a base hit. I'd enjoy very much reading comments about and criticisms of this idea.