Nas wrote:
Jaw Breaker wrote:
For those who have followed the debate over switching to an electronic strike zone, I have a question: do the errors predominantly favor the hitter (i.e., human umps are calling too many actual strikes as balls) or vice versa?
I think far more balls are being called strikes.
It varies from ump to ump (which is a
problem right there), but the data supports on average +10 strikes per game per game. That is, the average ump calls 10 more outside the zone pitches strikes vs calling inside the zone pitches balls. All umps make mistakes both ways, but the mistakes tend to favor the pitchers.
Real Sports had a
Man vs Machine segment covering the research of a professor from the notorious party school Yale who highlighted data backing up the assertion that umps make mistakes and the mistakes favor home teams e.g., game 7 of the 2011 World Series:
Quote:
Our Game 7 data shows that the home plate umpire (Layne) missed 14 calls in favor of the home team Cardinals – against only three for the
Rangers.The Yale prof also presented data showing that umps favored big-name pitchers and they did so more than giving calls to prominent hitters.
In addition to every ump having a different strike zone and individual umps strike zones changing over time; umps favoring home teams; umps favoring name pitchers--umps are really bad at calling close pitches, possibly an example of "the gambler's fallacy" in action. [flip a coin 5x's in a row and have it come up heads every time, majority of people will favor the next flip being tails, even tho the odds of it being heads or tails haven't changed]
Quote:
MOSKOWITZ: "So the thought experiment was as follows — take two pitches that land in exactly the same spot. The umpire should be consistent and call that pitch the same way every time. Because the rules state that each pitch is independent in terms of calling it correctly — it’s either in the strike zone or it’s not."
The first thing the PITCHf/x data shows is that umpires are, generally, quite fallible.
MOSKOWITZ: "On pitches that are just outside of the strike zone – they’re definitely balls, but they’re close – on those pitches, umpires only get those right about 64 percent of the time. So that’s a 36 percent error rate, it’s big."
DUBNER: "Slightly better than flipping a coin, but not much."
MOSKOWITZ: "Not much. Better than you and I could do though, I would say."
So if an ump has called the last close pitch a strike or the last 2 close pitches strikes, the data shows that they're more likely to call the next close pitch in the same spot a ball.
And umps mistakes cluster around high-leverage situations as well. Umps calls are more accurate on the first pitch of an at bat than they are on say a 3-2 pitch with the bases juiced.