Win Probability Added

Win Probability Added is a sabermetric designed to estimate a player's value, with leverage ("clutch") taken into account. It works by calculating the probability of a team winning for each possibility of bases occupied, outs, inning, and score. The difference between the win probability before and after the event is the Win Probability Added. Adding the value from each of the player's plate appearances or batters faced gives you total Win Probability Added.