Maybe This is a Victory of Sorts

The NYT reports on what looks like a well-reasoned study on officiating bias in the NBA.  I say well-reasoned mainly because Steven Levitt, who has become famous for applying tools of economics to such problems, seems to be comfortable with their approach.  The key finding is that white refs call fouls on black players at a rate .12-.20 fouls per 48 minutes playing time higher than they do on white players  [note that most players don't play a full 48 minutes per game, so the actual rate per player per game is less].  Black refs show the same tendency to call more fouls on whites, though the article omits this rate.

That's obviously a bummer -- we'd like to think that stuff never comes into play.  However, I would like to offer this bit of perspective:  Sixty years ago, black men were not allowed in the NBA.  Today, black men in the NBA, along with folks like Tiger Woods, are among the highest salaried people in the world.   In 60 years, we have gone from  total exclusion to a measurable difference of about 1 foul called every 10 or so games played.  That's pretty good progress. 

My sense is that we make snap decisions about other people based on a wide range of physical attributes, including height, attractiveness, clothing, tattoos, piercings as well as visible racial characteristics (e.g. skin color) and race-related appearance choices (e.g. cornrows).  It would be interesting to see where skin color falls against these other visible differentiators as a driver of third party decisions (e.g. whether to call a foul).   My sense is that 60 years ago, skin color would be factor #1 and all these others would be orders of magnitude behind.  Today?  I don't know.  While skin color hasn't gone away as an influencer, it may be falling into what we might call the "background level", less than or equal to some of these other effects.  It would be interesting, for example, to make the same study on level of visible tattooing and the effect on foul calls.  My sense is that this might be of the same order of magnitude today as skin color in affecting such snap decisions.


  1. mjh:

    Isn't there an assumption here that black players and white players commit fouls at roughly the same rate? What if white players commit more fouls? In that case, it'd be correct for the black refs to call more fouls on them. It would demonstrate evidence of bias amongst the white referees. The same goes if black players commit more fouls than white players.

    What is being measured here: Are the tendancies of the refs being measured by the amount of fouls that they call, or are the tendancies of the players being measured based on how many fouls are called on them? Is there a way to even measure the tendancies against an objective reality of what is or isn't a foul?

    I haven't read the entire paper, but this part seems pretty important:

    Ideally we would like to know how many fouls were called by each referee against each player. However, the NBA boxscore only provides the number of fouls called on each player and the names of the three officials for each game. Thus while we cannot observe the referee who blows the whistle for each foul, our empirical strategy involves comparing the number of fouls each player earns when particular referees are present.

    What if a group of players commits 0.3-0.5 extra fouls per game than a different group. Then the fact that they only get called for 0.2 extra fouls is bias in the other direction. They get away with 0.1-0.3 extra fouls per game.

    NOTE: Please don't misunderstand. I'm not trying to justify anything. I don't like/watch the NBA. If there is bias, I would want that eliminated. I just want to understand how a study can claim bias without comparing the bias to an objective standard.

  2. BobH:

    Like mjh, I'm not a fan of the NBA. Among those who do, though, many say that there is a difference in playing style between blacks and whites (or, perhaps, that there is an urban "playground" style, practiced mostly by blacks).

    Is it possible that this different style results in more fouls?

  3. BobH:

    Like mjh, I'm not a fan of the NBA. Among those who do, though, many say that there is a difference in playing style between blacks and whites (or, perhaps, that there is an urban "playground" style, practiced mostly by blacks).

    Is it possible that this different style results in more fouls?

  4. Rick Caird:

    Somewhere today, it was pointed out that most fouls are called inside. It was also pointed out that many of the white players are guards and play on the outside. As an example, guards rarely get called for rebounding fouls. This "study" is clearly a case of incompletely analyzed data. Before you could make any analysis, you would have to look at "fouls per position" or where on the court the fouls were called.

    In other words, this whole thing is a waste.


  5. Ray G:

    That's it! I'm boycotting the NBA until, . . . until, . . . hmm, I don't reall care actually. Never mind.

  6. dearieme:

    Mr Half Sigma ( claims that the NYT has got the story arsy-versy.

  7. Roy Lofquist:

    This reminds me of many studies that show that "getting hot" and "streaks" have no statistical basis. Anybody who has played sports know that these guys are like celibates pontificating about sex.

  8. Anon:

    Did anyone actually carefully read the article or the study? It doesn't say that black players get more fouls than white players, and thus there is racism. That would be an obvious flaw in reasoning.

    What it says is that a player gets more fouls when officiated by an opposite-race referee. And the statistic quoted from the article is wrong. The key finding is not that white refs call more fouls on black players than they do on white players. It is that a black (white) player receives more fouls when officiated by white (black) referees than when officiated by black referees.

    Sorry to sound exasperated, but this is not the first time I've seen sloppy reading/analysis on this blog.