from Amazon
Wednesday, July 11, 2007
Where is the strike zone exactly?
Yet another in a long-series of great research pieces by John Walsh.
He points out to some obvious data quality issues like:
”...all I can say is that one pitch whose recorded location was right in the heart of the strike zone, was actually an intentional ball that was thrown two feet off the plate!”
Generally speaking, we see that the textbook strike zone should be the 17-inches of the plate, plus the inside/outside pitches where the ball knicks the plate. Since the datapoint is measured at the centre of the ball, that means that the center-of-ball to center-of-ball left/right strike zone would be a total of almost 20 inches. Umpires however are calling the left/right center-of-ball strike zone as 24.1 inches for RH and 24.5 inches for LH. Dan Fox once pointed out that the home plate also has the outside rubber, which could technically be considered part of the home plate. That would bridge some of that gap, but not all. As well, since John is considering all umpires, it would be interesting to see the left/right range of each umpire. After all, the good ones would call the 20 or 22 left/right strike zone, while the bad ones would call a 25-27 strike zone. You won’t have, I don’t think, umpires who call a 17-18 inch strike zone to balance it out.
John also shows a skew depending on the handedness of the batter. I have to confess I don’t know exactly where the umpire positions himself. In yesterday’s All-Star game, the old man got knocked heavily twice on his left-side, with righties at bat. I didn’t pay attention as to where he was positioned when lefties were at bat. I’m guessing the ump positions himself away from the catcher’s throwing hand, so, he would be farther away from a LHB than a RHB.
Fun stuff…