Is calling a foul a black & white decision?

Justin Wolfers has a piece of research featured on the front page of the New York Times today. And it’s a very nice story.

A coming paper by a University of Pennsylvania professor and a Cornell University graduate student says that, during the 13 seasons from 1991 through 2004, white referees called fouls at a greater rate against black players than against white players.

Justin Wolfers, an assistant professor of business and public policy at the Wharton School, and Joseph Price, a Cornell graduate student in economics, found a corresponding bias in which black officials called fouls more frequently against white players, though that tendency was not as strong. They went on to claim that the different rates at which fouls are called “is large enough that the probability of a team winning is noticeably affected by the racial composition of the refereeing crew assigned to the game.”

The NBA clearly saw the potential for bad publicity when Price & Wolfers sent them a draft version in 2006, so they commissioned their own paper. So the New York Times did an interesting thing.

Three independent experts asked by The Times to examine the Wolfers-Price paper and materials released by the N.B.A. said they considered the Wolfers-Price argument far more sound. … The three experts who examined the Wolfers-Price paper and the N.B.A.’s materials were Ian Ayres of Yale Law School, the author of “Pervasive Prejudice?” and an expert in testing for how subtle racial bias, also known as implicit association, appears in interactions ranging from the setting of bail amounts to the tipping of taxi drivers; David Berri of California State University-Bakersfield, the author of “The Wages of Wins,” which analyzes sports issues using statistics; and Larry Katz of Harvard University, the senior editor of the Quarterly Journal of Economics.

(BTW, the Times made a mistake in asking Katz. While he’s a great economist, he was also one of Justin’s thesis advisers, which creates an appearance of partiality. But I don’t think there’s any such issue with Ayres or Berri.)

The Price-Wolfers analysis was based on NBA games from 1991/92 to 2003/04, so you might wonder whether the bias is still as pronounced. To answer that question, they re-run the model using 2004/05 to 2006/07 games, and find very similar estimates.

I don’t find the results at all surprising. If you were ever going to find discrimination, you’d find it in a context that forced people to make snap decisions. Don’t believe me? Try the Implicit Association Test.

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3 Responses to Is calling a foul a black & white decision?

  1. Pingback: Club Troppo » The end of ‘he said - she said’ journalism?

  2. I did the implicit association test a couple of years ago; I have the same problem as the referees.

  3. Sinclair Davidson says:

    Some first impressions:

    (1) Larry Katz should have known better and not be involved. In these ‘appeal to public’ issues, any sign of partiality becomes a perception problem that is (often) totally unrelated to the issue.

    (2) We have a group of academics evaluating an academic paper (aimed at an academic audience) compared to a non-academic paper (albeit trying to debunk the first paper) aimed at a lay-audience. Are we surprised the academics find the first more persuasive? Irrespective of the merits (and I’m sure they’re substantial) academics are going to prefer an academic paper to a non-academic paper. How closely do you engage when reading a journal article relative to a newspaper relative to a blog post?

    (3) NBA is basketball? I have seen other papers that imply some type of discrimination in basketball before (I seem to recall James Koch did work in this area). The identity of players is clear. Why not replicate the study with games where the identity of players is less clear? For example in US football the referee (umpire?) makes snap decisions, but can’t easily see the players identity, we expect a smaller effect. Similar in soccer, snap decisions, but the player is known, we expect a larger effect, and so on.

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