A. Where does the study ever control for a pitcher's "wildness"? I read it and I didn't see it (maybe I missed it, I'm just asking you to point it out to me; maybe even quote that part in your post so I can see it )
B. It is 3 years of data, but still, there are a small number of pitchers who have a large effect on the study for both the Blacks and Asians (notably SP that pitched all of those 3-4 years).
C. So umpires are racist against their own race? Seems kind of odd to me....
A. There are three different ways they controlled for this in the study. First, they control for what the count was when the pitch was thrown. Wild pitchers will be often be in counts where they are behind, so this variable controls, to some degree, for wildness. Second, they report in footnote 10 that they also estimated models with walks per inning as a control and found it did not change the results. Third, they use a statistical method known as "fixed effects". This method essentially uses each player as their own control; a fixed effect is a statistical technique that controls for unmeasured features of an observation. In other words, things that are inherently part of each pitcher's make-up (wildness, toughness, etc.) are controlled through this technique.
B. Even a pitcher that averaged 100 pitches per game and pitched 35 games in all three years represents less than 20 percent of the black sample...and the model still achieves significance, despite your concerns.
C. No, umpires are biased against the opposite race. That bias is moderated and possibly even eliminated or reversed when they are monitored by Questec or are in situations where they may be more likely to consciously self-monitor their behavior. Since there are far more situations where an umpire's subconscious biases appear to be operating, however, the net result is that pitchers who are of the opposite race of the umpire get fewer strike calls, controlling for other factors. Over the course of a season, a team that tried to match its pitcher to the race of the home plate umpire would gain a 2-4 win advantage (theoretically; there would be huge practical problems in ding this). Also, since there are far more white umpires than black umpires, minority pitchers end up with worse results, and effectively earn lower salaries.
"I don't want to play golf. When I hit a ball, I want someone else to chase it."