Discrimination in MLB

You might recall the paper by  Price and Wolfers that made the rounds earlier this year, where the authors find that NBA referees appear to discriminate on the basis of race.  A new paper Parsons, Sulaeman, Yates, and Hamermesh explore the same phenomenon in baseball.  The abstract:

We explore umpires' racial/ethnic discrimination in the evaluation of Major League Baseball players.  Controlling for umpire, pitcher, and batter fixed effects and other factors, strikes are more likely to be called if the umpire and pitcher math race/ethnicity.  This effect exists where there is little scrutiny of umpires' behavior-in ballparks without computerized systems monitoring umpires' calls, at poorly attended games, and when the next called pitch cannot determine the outcome of the at-bat.  If a pitcher shares the home-plate unpire's race/ethnicity, he gives up fewer earned runs per game and improves his team's chance of winning.  The results suggest that atempts to measure salary discrimination generally may be flawed since the productivity measures can themselves be contaminated by the effects of racial preferences.

I haven't looked closely at the paper, but the dataset they've used seems to be much more detailed than that of the Price and Wolfers (please correct me if I'm wrong).  The authors know where each player and umpire was born and can reasonably determine their ethnicity upon this knowledge and with pictures available online.  Unlike Price and Wolfers, who only knew the racial composition of the crew in any game, the authors of the present paper know who the umpires are at each position for each pitch and who the players are when a play is made.  Moreover, there appears to be plenty of data available to reasonably categorize each player and umpire with a race an ethnicity.

Here's Skip's take with links to news stories about the paper.  I'll have more later.