Wednesday, May 18, 2005

Win Value Changed

I warned you that this is a work in process. Almost immediately after describing how Win Value works in this post, I revised it, based largely on this comment by loyal reader Backward K. I realized that the index run I used to calculate Win Value could be better. I originally used the average go-ahead run. Why not use the average run, regardless of score and inning? In other words, why not key Win Value off of Run Value? In part I didn't do this because I didn't think I had the right data, but I realized last night I did, and I recalculated the Win Value chart. Essentially the average run increases a team's chance to win by 8%, whereas the average go-ahead run is worth 16%. So, bottom line, this new approach doubles the WV from the old approach.

But, most importantly, it improves the ERV Player Charts, because you can now more directly compare a player's RV with his WV to see how that player does in the clutch (which is what Backward K was pointing out in his comment). I've revised the Wilkerson chart, and you can see now that for him the WV almost exactly tracks his RV, which says he performs almost exactly the same in the clutch as in other situations.

I'm not going back and redoing the boxscores, but will be using the new approach from here on out. If anyone wants an old boxscore with the new approach, send us an e-mail and I will send you one.


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