Tuesday, October 18, 2005

Win Expectancy

Many of you have probably seen this little tool floating around. In a nutshell, Phil Birnbaum took the time to gather the boxscores for every game between 1979 and 1990, with the help of retrosheet. Chris Shea then put together this nifty little calculator that allows you to put in the game situation as an input. It then gives you, as an output, the number of games between 1979 and 1990 that had the same situation, the number of times the team won, and thus a percentage of liklihood that a team can win a game in a certain situation. Check it out for last night's game.

9th inning

Start of the Inning - 5.6% Chance of a Cardinal Victory
John Rodriguez strikeout - 2.4%
John Mabry strikeout - 0.9%
David Eckstein single - 2.7%
David Eckstein steal - 1.1%
Jim Edmonds walk - 5.3%
Albert Pujols Home Run - 82.9%
Reggie Sanders strikeout - 81.1%

Obviously, the system isn't perfect, and the numbers shouldn't be looked at as pure odds. Not every team during the 11 year span in question had Brad Lidge as a closer, or Albert Pujols as a hitter. And the fact that Eckstein actually hurt the teams chances of winning by stealing 2nd is a fluke in the data.

But the fact remains. The Cardinals, with none on and 2 outs, had less than a 1 in 100 chance of winning that game according to this data. On the road, in the playoffs, facing a team that hadn't blown a 9th inning game all season? It was likely even more improbable.

Wow.

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