How some referees impact scoring

A statistical analysis of NBA referees reveals their proclivities and impact

Updated: March 29, 2013, 3:21 PM ET
By Neil Paine |

Manu Ginobili, Violet PalmerHoward Smith/US PresswireManu Ginobili pleads with ref Violet Palmer. Offensive efficiency increases in games she officiates.

For many casual NBA fans and observers, the Tim Donaghy betting scandal was the first occasion they had to think about specific referees' tendencies to call games certain ways. If you recall, in addition to influencing the outcomes of games he officiated, Donaghy used his inside knowledge of who was refereeing other games (and their officiating predispositions) to win bets at a startling rate of accuracy.

This wasn't news to NBA insiders, however. Players and coaches have long known that each referee has biases toward certain styles of play, and they have the proclivity to make certain calls more or less than their peers. In Sam Smith's "The Jordan Rules," the Chicago Bulls (and their opponents) often spoke of what kind of game it would be -- and what they would or would not be able to get away with -- based solely on who the officiating crew was that night.

More than two decades (and one enormous scandal) later, the NBA still has officials who have extreme tendencies, and there's no doubt that teams will be aware of them come playoff time. And considering the recent comments from LeBron James about hard fouls, teams like the Bulls and Indiana Pacers might have a better idea of what they will and won't be able to get away with.

Using a three-year weighted average of statistics from games officiated by each active NBA official, here are the biggest outliers to watch among referee trends (full chart at the bottom):

Neil Paine writes for FiveThirtyEight, the data-supported sports, politics and culture site coming soon from ESPN.