Bluematter.

A new paper by Wolfers and Price, covered in the New York Times, has been causing quite a stir recently. In short:

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.

This is a great piece of work, and the evidence presented is very convincing. However, I still have some doubts as to whether racial discrimination per se is indeed the driving force behind the results presented.

Consider these three facts:

First of all, interpreting the rules of the game is to some extent subjective, a truth every sports fan is familiar with. How much of a push constitutes a foul? How aggressive must a player get before having to be disciplined? How important is intention to foul?

Secondly, black and white players have different playing styles. This is not only due to physical characteristics and body types but also due to the different environments where black and white players learn to play basketball.

Finally, this also goes for the referees and their perception of what constitutes foul play.

Combining the above, it's very likely black referees grew up learning to interpret the rules of the game amongst a majority of black players, and so came to tolerate some 'black' playing behaviour that a white referee would not view so favourably - and vice versa. If this is indeed the case, the results in the Wolfers and Price paper could be driven by this fairly innocuous, colour-blind factor - the authors' research design does not allow us to distinguish between these two hypotheses.

So could this be a valid claim? I have my own anecdotal evidence to back the case. I am usually watching the football World Cup (soccer to my American readers) with an English friend of mine. Now, the Greek game is generally quite unspectacular and with a strong defensive element, while the English tend to play much more open and technical football. In many instances when calling a foul is not a clear cut decision (and there are many moments like this in a typical game), we often find ourselves disagreeing. Since this has happened quite a lot of times by now, I think I've spotted a pattern: I am generally way more lenient on players that tend to play strong defence, pushing and generally torturing their opponents, while he will be more forgiving of, say, unfriendly strikers trying to make their way into a defensive opponent's area.

And while it may be sport fan's paranoia, I think this is replicated in the field. My perception is that an Italian referee officiating a Greece v England game will generally be more 'friendly' to Greece than a Brazilian referee in charge of the same game. This has nothing to do with the Italians preferring mousaka to fois gras, but it has a lot to do with perception of the rules of the game and the environment in which this is developed.

Addendum: Despite the objections above, I still think there is a good chance the paper might showcase exactly what it says on the box. To see why, try the Implicit Association Test (thanks to Andrew Leigh for the link).