Looking For Drama? Look No Further Than cWPA

On Monday, the Rangers and Diamondbacks played a classic at Chase Field. It started as a pitcher’s duel between Jordan Montgomery, who pitched beautifully over eight scoreless frames, and a cadre of Diamondbacks pitchers led by bulk man Slade Cecconi, who allowed the only run of the first eight innings on a solo shot off the bat of Adolis García. Then, things got chaotic. From the ninth inning on, the game swung from an 88.4% chance of a Texas win to an 81.3% likelihood for Arizona, then back to 95.1% odds in favor of the Rangers before a final swing back to the D-backs on a Tommy Pham walk-off double. Not to be confused for the heart rates of each team’s fans Monday evening, the win probability chart came out looking like this:
Last week, Ben Clemens wrote about how neat Win Probability Added is, and its merits as a part of the MVP discussion. While Ben’s piece made the great point that WPA is not “just a storytelling statistic,” lobbying for its use in measuring value over a season, its storytelling powers are indeed pretty remarkable. So much of the drama within Monday’s game was made quantifiable by measuring the shifts in win probability. Ketel Marte’s game-tying homer in the ninth was worth .467 WPA, or 46.7 percentage points of win probability; Nathaniel Lowe’s go-ahead double was worth .454; Tommy Pham’s walk-off was worth .754, the 11th-highest WPA value for any single play this year. That’s three hits that turned the game on its head, and then back on its feet, and then back on its head again. Read the rest of this entry »