15 June 2008

Orioles Recap: Oh So Fickle

I typically never run recaps because you can easily find your descriptive columns elsewhere. At Camden Depot we try to go underneath the surface and try to explain how things happened or what will happen. Last night though is a good time to introduce leverage index values and winning probability added. These two statistics are collected by FanGraphs.

Here is the graph from last night's game:

Winning Probability (WP) is shown on the top graph. Essentially, the statistic is based on the probability of a certain result in relation to the score, inning, and outs affects a team's chances to win. This is often expressed as Winning Probability Added (WPA). This try to discern how different players producing certain events affect changes in WP. For instance, Salazar's homerun increased the Orioles' chances of winning by ~40%. His WPA for the single event would be 0.40 and this would be added to his other events during the day. His final WPA for yesterday's game was .321 and was third among Orioles' hitters for the day.

Leverage Index in the bottom graph. Basically, the greater your value, the greater the probability in winning is shifted. For instance, in the top of the first inning, you can see that the leverage decreases as each out is made. In relation to other innings, the leverage is low because the game is tied and there are plentiful opportunities to score runs later. A run in the first has less meaning than a run in the ninth because the opposing team has less opportunity to score that single run back to even it out. Another example would be in the top of the ninth when George Sherrill entered the game. The leverage starts high because the Orioles have a one run lead and the Pirates have no outs. It then becomes greater with Nady's single to right. After LaRoche's home run, the leverage is almost nothing because there is no one on and the Orioles are down by a run.

Hopefully, you found this interesting.

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