Dave Studeman calls Win Probability Added (WPA) the "ultimate story stat." WPA uses Tom Tango's win expectancy tables to measure a team's probability of victory (ergo, win expectancy) following every play. From these data, we can interpret several different characteristics of the game, including how close it was, how exciting it was and what the biggest plays of the game were. We can also take each change in win expectancy, credit it to the pitcher and batter (or baserunner) involved in the play, and measure their contributions by the sum of all those credits. That's what WPA is.
By combining FanGraphs' WPA numbers and my World Series projections, I aim to depict and uncover the stories of the 2015 World Series in the same way. How close was it, really? What were the biggest plays? Who was on the mound, in the batter's box and on the base path when the biggest plays happened, and what does the sum of the swings in win expectancy say about who the biggest contributors were?
You can read my answers to these questions below, and answer your own questions by using the interactive 2015 World Series Win Expectancy chart.