THE BOOK--Playing The Percentages In Baseball

Tuesday, January 18, 2011

WPA story at ESPN

Peter does a good job at bringing light to WPA:

But the best thing about Win Probability is that it captures, like no other stat, how we viscerally experience sports. As fans, we carry in our guts a reflexive, fuzzy calculation of our team’s chances of winning a game—a nervous tension that explodes after triumphant plays and collapses after moments of agony. Win Probability expresses that emotion with mathematical precision.
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“I introduced my first WPA story the day after the Bartman/Cubs collapse game in 2003,” says Tom Tango, co-author of The Book: Playing the Percentages in Baseball. “How can you capture that game with numbers? I think only WPA could do it. It’s a story stat.” In the eighth inning of that notorious playoff game against Florida, the Cubs’ Win Probability crashed from 95.6 percent to 1.8 percent, according to Tango’s calculations. But Steve Bartman’s interference caused just 3.1 percentage points of the plunge.
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Is there anything Win Probability can’t do? Well, yes. If you’re trying to figure out whether Joey Votto is going to outhit Prince Fielder next year or how much the Reds should pay their MVP, this is not your stat. WPA looks back, not ahead; it measures accomplishment, not skill.

But you know when you watch poker on TV, and the screen displays each player’s chances of winning as the cards come out? And how you don’t really need to understand anything about flops or implied odds to pick up the flow of a game—you can just figure out what’s happening as those little percentages change? Those numbers are Win Probabilities. And it’s only a matter of time before they start popping up during baseball or football broadcasts. Unobtrusive? Check. Easy to comprehend? Check. Revealing? Check. Best of all, unlike most Next Great Stats, it’s not just about brains. It’s also about the heart.