Wednesday, May 02, 2007

Reffing it old style 

An economist made news today in the NY Times by showing bias in the calling of fouls in NBA games. (I know, I must have NBA on the brain today.) Here's a link on the fellow's home page to his paper. The bias worked in both directions, but was "more pronounced" from white officials to black players. Some of us on a sports economics mailing list have been discussing this today. Here are some comments motivated by that and the article:
  1. Since when does the Times get independent experts to referee a working paper? (I know two of the three, and I'd respect their opinions.) Would that they were this careful with some of their political coverage!
  2. The mailing list participants were trying to figure out the size of the effect, and it appears to be between 3-4 games a year. It thus might help a team marginally in the playoffs to add a white player in place of a black player. That's a serious charge, and part of the reason for the NBA's very heated denial.
  3. The denial includes an in-house study by an accounting firm that had, unlike the academic paper, access to information on which referee called which foul. (There are three referees on the floor.) But tellingly the Times reports, "The league�s study was less formal and detailed than an academic paper, included foul calls for only two and a half seasons (from November 2004 through January 2007), and did not consider differences among players by position, veteran status and the like." The academic study shows that which controls are used to hold constant various player and game characteristics changes a good bit of the results (though their base conclusion seems quite robust.) When the NBA president of operations Joel Litvin says the NBA "concluded unequivocally that there was no racial bias in officiating," that's spinning. No study can say that unequivocally.
  4. It's worth noting that black players typically get called for fewer fouls than white players anyway, because most white players are, in the study's words, "generally taller, heavier, and more likely to play center (all factors that make them more likely to commit fouls). The more striking fact is that the gap in the number of fouls called against black and white players changes as the number of white referees increases (dropping from -0.827 to -0.574)." It's not so much that black players get called for more fouls, but that white referees call fewer fouls in general and specifically fewer against white players.
  5. And I think that's important because they find a number of game characteristics that differ depending on the number of white refs. The paper alludes to the fact that not only are white and black players in the NBA different physically but also in style of play. Black referees might like the style of black players and white referees the style of white players. That doesn't make one group right and the other wrong. I grew up in the 1970s watching different styles of play; we talked about East Coast ball being rougher than West Coast play.
My guess is that if they could go back and collect data on the age of referees, they'd find something. Older referees are probably more often white. Older referees may have preferred that rougher, Celtics-Bullets style of play, or otherwise let them play. Younger referees may prefer the creative one-on-one game. Suppose it's old/young rather than white/black? I don't know, but I know not to use the word "unequivocally" loosely.