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Wednesday, September 07, 2011
Reader Mail of the day: WPA fails as story stat?
Partial mail:
I’d like to comment on a shortcoming that WPA has as a story stat. Or to use your analogy, I maintain that there are cases where the screwdriver screws the wrong screw. I still love the stat though.
WPA does a great job when the story is batter vs. pitcher. As this is the main story line in most games, WPA gets it right most of the time. However, whenever the story relates to fielding, WPA misses the boat. What bothers me is not so much that it doesn’t credit great/terrible fielding, but apportions both the credit and the blame to the wrong players.
My best example is one of my most favorite games, Yankees vs. Mets on June 12th 2009. With the score in favor of the Mets 8-7, bottom of the 9th, men on 1st & 2nd, 2 outs, A-Rod hit a pop up off K-Rod to Luis Castillo. He dropped the ball and the Yankees won. A-Rod was awarded 0.818 WPA points (I think perhaps the most in his career for a single play!) and K Rod “awarded” -0.818. Neither of them deserved either the credit or the blame.
Similarly, in cases where a 1st baseman makes a tremendous play and turns an unassisted double play by doubling off the runner, the pitcher receives all the credit, the batter all the blame, while the fielder receives nothing.
My response:
There’s nothing in WPA that prevents the awarding of the play to the fielders.
I will point you to the very first time I did WPA, where I go out of my way to talk about Moises Alou, and Gonzalez, and really, all the fielders. NEVER do I say it was ONLY Mark Prior.
http://www.hardballtimes.com/main/article/crucial-situations
That Fangraphs or BR.com does not have the fielding data to do the split is not a problem with WPA. It’s a problem with them, or rather, the lack of data that describes the fielders in detail.
I’ll also point out that WPA only described who was INVOLVED. It does NOT try to establish who was RESPONSIBLE. In the above example, ARod and KRod were involved. Now, it would be nice if Fangraphs and BR.com captures the fielders as well. But capturing fielders is really not so clean. The best example there is that the 1B is simply the end point of the putout, and he is basically “just there”. Was he “involved”? You can make the case that he was involved. You can also make the case that he was incidental.
If someone wants to create a process for WPA that also includes the fielders, then go ahead. You may get to the point that it ends up hiding the story you are trying to show.