March 30, 2014

Umpires Call 1 Out Of Every 7 Non-Swinging Pitches Incorrectly

Brayden King, New York Times:
After analyzing more than 700,000 pitches thrown during the 2008 and 2009 seasons, we found that umpires frequently made errors behind the plate — about 14 percent of non-swinging pitches were called erroneously.

Some of those errors occurred in fairly predictable ways. We found, for example, that umpires tended to favor the home team by expanding the strike zone, calling a strike when the pitch was actually a ball 13.3 percent of the time for home team pitchers versus 12.7 percent of the time for visitors.

Other errors were more surprising. Contrary to the expectation (or hope) that umpires would be more accurate in important situations, we found that they were, in fact, more likely to make mistakes when the game was on the line. For example, our analyses suggest that umpires were 13 percent more likely to miss an actual strike in the bottom of the ninth inning of a tie game than in the top of the first inning, on the first pitch.

We also found that the pitch count had an influence over the umpire's perception of a pitch. When the count was 3-0, and another ball would end the at-bat, the umpires mistakenly called a strike 18.6 percent of the time, compared with a 14.7 percent error rate when the count was 0-0. But when the count was 0-2, with another strike yielding a strikeout, the umpires expanded the strike zone only 7.3 percent of the time, half the error rate for 0-0. The umpires, in other words, appeared biased against ending an at-bat. ...

Baseball insiders have long suspected what our research confirms: that umpires tend to make errors in ways that favor players who have established themselves at the top of the game's status hierarchy. ...

Technologically, Major League Baseball is in a position, thanks to its high-speed camera system, to enforce a completely accurate, uniform strike zone. The question is whether we, as fans, want our games to be fair and just, or whether we are compelled to watch the game because it mimics the real world, warts and all.
Robots! Now!


FenFan said...

I'm still not in favor of taking the balls and strikes out of the umpires hands, even if the technology exists, but I am in favor of using it to grade umpires and then assign post-season work and negotiate future work based on those grades.

There is (I believe) a glut of talent at the minor league levels that would love a major league paycheck and I see no reason not to use this fact to force umpires to stop making calls biased by the pitcher or the batter.

Tom DePlonty said...

It might be wrong to assume that the error rate can be changed by giving umpires different incentives. The task may just be very hard for humans to do accurately, and all the systematic biases really reflect is that inherent difficulty. (Is it any surprise that star players tend to get close calls?) If you change the incentives, in other words, you may change the biases without improving accuracy. I'm with Alan: why not robots? What's the compelling argument for continuing to use human umpires at these error rates, except for the appeal to tradition?

FenFan said...

Didn't you ever see I, Robot? :-D

In my view, the study has created a baseline where the league can start to correct these biases. While I agree that a human may be challenged to call balls and strikes as accurately as a high-speed camera system, why NOT see whether performance can improve to a point where the benefits of such a system would be negligible?

Tom, your points are valid but I, for one, need more data to validate your hypotheses (and my own).

I'm a BIG proponent of instant replay but mentally I'm not ready to take that next step unless further research shows that we cannot improve umpire accuracy in other ways.