Baseball Musings
Baseball Musings
January 20, 2009
Analyzing Umpires

Josh Kalk uses PITCHf/x to study umpires strike zones and finds as a group MLB umpires are excellent ball-strike callers:

If you do this for all umpires, then you can start studying them as a group. You can ask how often they correctly identify a pitch compared to the MLB rule definition (accuracy), how often they correctly identify a pitch compared with their personal strike zone (precision), and how large these strike zones are compared to the MLB strike zones (size) for both left- and right-handed batters. When you do this, the first thing that jumps out at you is just how accurate and precise major league umpires are as a group. While they tend to give the outside corner a bit too much and are a bit stingy near the top and bottom, for the most part a pitch over the plate is called a strike and almost always a pitch that is thrown within a specific umpire's zone is called a strike. Of the 82 umpires who were behind the plate when the PITCHf/x cameras were working last year, even the least consistent was very consistent.

That's good to know. PITCHf/x should also prevent an NBA type scandal. We should be able to tell if an umpire becomes inconsistent at key points in a game, throwing it to one of the opponents.


Posted by David Pinto at 09:09 AM | Umpires | TrackBack (0)
Comments

Most of this blog post centers on Angel Hernandez, and the blogger tries every adjustment known to man to get Hernandez to look better. But even after all the questionable adjustments, Hernandez calls a lot of pitches off the outside corner strikes. The blogger still declares that Hernandez is a terrific umpire, which to me indicates pretty low standards of terrific-ness.

My guess is that the outside corner will be called a lot tighter this year. Baseball needs all the offense it can get in a bad economy. Making the pitcher actually throw the ball over the outside corner to get a called strike will boost offense more than all the steroids ever synthesized.

Posted by: Casey Abell at January 20, 2009 09:27 AM

They should also focus of keeping balls and strikes consistent throughou the count and the game. MLB umpires love to call guys out in big situations.

Posted by: bandit at January 20, 2009 11:39 AM

I hope Josh doesn't get too much heat from MLBAM over this. When I discussed umpire analyis at the PITCHf/x Summit, well, I'll just say MLBAM made it very clear what they thought about that. Specifically, they realize they can't stop private individuals from publishing the work, but they did make it very clear they'd consider pulling all the available data "if that's the direction this goes". I purged my site of the work to avoid further feather ruffling. MLB teams are contractually forbidden from using PITCHf/x to analyze umpires, that's how seriously they take this.

Posted by: Harry Pavlidis at January 20, 2009 06:36 PM
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