Racial Bias In NBA Refereeing?

I’ve blogged before about my friend Justin Wolfers’ research on point shaving in college basketball and the death penalty.

Now Justin is back stirring up more controversy with a paper that claims that there is racial bias on the part of NBA referees, written up in the New York Times by Allen Schwarz. The claim of the paper is that Black officials call more fouls on White players and vice-versa.

I’ve read through the paper and could not find any mistakes. It appears to be carefully done. It mirrors findings John Donohue and I have in a different context. We found that when police departments hire more White officers, arrests of minorities rise, but not arrests of Whites. The opposite is true when more minority officers are hired.

One other thing worth noting. I have never seen a reporter (other than Dubner, of course) take more care to try to get the facts and interpretation right than Allen Schwarz did on this piece. He was in contact with me a number of times and even arranged to have the NBA’s counter-analysis evaluated by independent experts. Hats off to him for his reporting.

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  1. Chris Mealy says:

    Levitt is such a softie I took his praise with a grain of salt. But it’s completely deserved. I was startled by the paper’s depth and care. I’ve never seen a paper test so many hypotheses, and not obvious ones either.

    This paragraph seems to be the big payoff:

    There are also two ways in which these own-race biases may emerge: they may reflect referees favoring players of their own race, or alternatively disfavoring those of the opposite race. The arbitrary assignment of referees to games means that we can test whether our estimates reflect an influence of referee race on black players, or on white players. Table 3 is instructive, showing that the rate at which fouls are earned by black players is largely invariant to the racial composition of the refereeing crew. By contrast the rate at which fouls are earned by white players responds quite strongly to referee race. Further regression-based tests yield a similar pattern (see in particular the coefficient on %white referees in Table 4), suggesting that the impact of the biases we document is on white players, who are either favored by white referees, or disfavored by black referees.

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  2. Chris Mealy says:

    Levitt is such a softie I took his praise with a grain of salt. But it’s completely deserved. I was startled by the paper’s depth and care. I’ve never seen a paper test so many hypotheses, and not obvious ones either.

    This paragraph seems to be the big payoff:

    There are also two ways in which these own-race biases may emerge: they may reflect referees favoring players of their own race, or alternatively disfavoring those of the opposite race. The arbitrary assignment of referees to games means that we can test whether our estimates reflect an influence of referee race on black players, or on white players. Table 3 is instructive, showing that the rate at which fouls are earned by black players is largely invariant to the racial composition of the refereeing crew. By contrast the rate at which fouls are earned by white players responds quite strongly to referee race. Further regression-based tests yield a similar pattern (see in particular the coefficient on %white referees in Table 4), suggesting that the impact of the biases we document is on white players, who are either favored by white referees, or disfavored by black referees.

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  3. cisenburg says:

    Let us not forget that causation is independent of correlation.
    Is it possible that white players commit more fouls when the referees are black? It seems unlikely, but this blog consistently discusses the unlikely.

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  4. cisenburg says:

    Let us not forget that causation is independent of correlation.
    Is it possible that white players commit more fouls when the referees are black? It seems unlikely, but this blog consistently discusses the unlikely.

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  5. chappy8 says:

    I guess I wonder a couple of things:

    1/ This study doesn’t actually have data on WHICH referee actually called the foul, just the racial compostion of the crew, so we have no idea how this is distributed.

    2/ I couldn’t figure out if ‘end-of-game’ minutes or ‘blow-outs’ are really controlled for. Anyone that watches a lot of basketball knows that there is a flurry of fouls at the end of games. Not sure if there might be substitution patterns that could affect this. Of course a game that is a late blow-out might witness the opposite affect. Just wondering how these results might change if end of game minutes (in a ‘blow out’ versus ‘close’ game) might change things.

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  6. chappy8 says:

    I guess I wonder a couple of things:

    1/ This study doesn’t actually have data on WHICH referee actually called the foul, just the racial compostion of the crew, so we have no idea how this is distributed.

    2/ I couldn’t figure out if ‘end-of-game’ minutes or ‘blow-outs’ are really controlled for. Anyone that watches a lot of basketball knows that there is a flurry of fouls at the end of games. Not sure if there might be substitution patterns that could affect this. Of course a game that is a late blow-out might witness the opposite affect. Just wondering how these results might change if end of game minutes (in a ‘blow out’ versus ‘close’ game) might change things.

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  7. RutgersPainTrain says:

    I haven’t read the paper but the NY Times article seemed to imply that the researchers counted the composition of the 3 refs instead of counting which of the refs (white or black) were blowing the whistle each time. Is it possible that when there is only 1 black ref, he feels he needs to be tougher in the eyes of the two white refs and therefore calls more fouls on black players?

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  8. RutgersPainTrain says:

    I haven’t read the paper but the NY Times article seemed to imply that the researchers counted the composition of the 3 refs instead of counting which of the refs (white or black) were blowing the whistle each time. Is it possible that when there is only 1 black ref, he feels he needs to be tougher in the eyes of the two white refs and therefore calls more fouls on black players?

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