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In the June issue of American Economic Review, four scholars unpack the theory that MLB umpires express racial bias when calling strikes. In turn, pitchers throw balls that allow for less subjective judgment.

Here's the article's abstract:

Major League Baseball umpires express their racial/ethnic preferences when they evaluate pitchers. Strikes are called less often if the umpire and pitcher do not match race/ethnicity, but mainly where there is little scrutiny of umpires. Pitchers understand the incentives and throw pitches that allow umpires less subjective judgment (e.g., fastballs over home plate) when they anticipate bias. These direct and indirect effects bias performance measures of minorities downward. The results suggest how discrimination alters discriminated groups' behavior generally. They imply that biases in measured productivity must be accounted for in generating measures of wage discrimination.

Read the full article here (PDF).

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