The excellent blog Empirical Legal Studies has this timely entry on a recent paper by Joseph Price (Cornell, Econ–grad. student) and Justin Wolfers (Penn, Wharton) entitled Racial Discrimination Among NBA Referees.
The paper compares the rates at which white referees call fouls on black players (and black referees call fouls on white players), and concludes there is racial bias “sufficiently large that we find appreciable differences in whether predominantly black teams are more likely to win or lose, according to the racial composition of the refereeing crew.”