Race and refereeing

Two ivy league economists claim in a new study the outcome of NBA games may be affected by the race of the referee. Their conclusion:

We find that players have up to 4% fewer fouls called against them and score up to 21⁄2% more points on nights in which their race matches that of the refereeing crew. Player statistics that one might think are unaffected by referee behavior are uncorrelated with referee race. The bias in foul- calling 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.