Study Finds That NBA Refs Make Biased Calls

In a split second, a basketball referee has to make a call: to foul or not foul a player. In a recent study done by a former Cornell graduate student, it was found that these quick decisions are affected by more than just the game.
Joseph Price PhD ’07, who studied economics, worked with Prof. Justin Wolfers, Wharton, to examine nearly 13,000 National Basketball Association games between 1991 and 2002 to find evidence of an inherent racial bias in referee calls.
Price became interested in racial biases after reading a book on the topic as an undergraduate and from there went on to study the NBA.
He chose to study the NBA because he found it to be a “perfect setting” due to the small set of referees and players who are constantly and repeatedly interacting. The NBA also provided a good sample because of the multitude of people observing the referees.
The NBA is composed of 83 percent black players and 68 percent white referees, which also made for an interesting dynamic to examine.
“We aren’t limiting ourselves to sports, but the purpose of using a sport setting is to teach us how people make decisions and how this has potential implications for all of us. We all make decisions on who to work for, who to higher, where to shop, who to be friends to and those could all be effected by implicit biases,” Price said.
Price examined the box scores of the NBA games, which he explained are published statistics in newspapers of which players played, how many minutes they played and how many fouls they received. At the bottom of this box score are the names of the referees.
Price and Wolfers then looked at images of the players and referees to decide their race, which were classified as either white or not-white, something Price explained was more effective than using a reported race because with implicit biases, the decisions are based on what one sees.
They found that when there is an interaction between two people of the same race, there are less fouls called then when there is an interaction between two people of opposite races.
“The difference in fouls is about .182 fouls for every 48 minutes played, which is about a 4-percent effect. This is a small change, but it actually ends up changing who wins the game,” Price said.
“For a given player, he will only see a foul increase of about one for every 10 games played so you wouldn’t really expect him to notice,” Price said.
Because the NBA league is so competitive, small differences like this can make dramatic effects. Price explained that when betting on these games with this data, the researchers could beat the betting spread 62 percent of the time, which resulted in an 18 percent return on the money. Unfortunately, he said, because the referees and bookers know about this study, it is unlikely that people would still be able to profit off of the information.
When the NBA got wind of the data, NBA Commissioner David Stern did his own study, in which he denied detecting any racial biases in referee behavior. These results were not made public.
Stern said, “are the most ranked, rated, reviewed, statically analyzed and mentored group of employees of any company in any place in the world,” according to Price.
Had the NBA acknowledged this bias, Dr. Anthony Greenwald, a professor of psychology at Washington University, believes some of the evidence of the racial discrimination would disappear.
Greenwald, who researches these implicit unconscious decisions, does not think a person’s inherent bias will go away, but if people are aware of these biases, they will be motivated to do something to prevent them from affecting their behavior.
When the decision is made in a split second, like in basketball, making conscious choices becomes more of a challenge.
Greenwald said, “The shorter the time they have, the more difficult it is to do something, but if they know about it in a general way in advance, they can be prepared in different ways to make these judgments.”
According to Greenwald’s testing, 75 percent of people have an inherent racial bias, compared to the 10 percent who report being aware of their bias. Greenwald also did his own study on the NBA data, and found, using an alternate method, the same inherent racial bias.
In response to Stern’s study, Greenwald doubted the NBA could do a study as thorough as Wolfer and Price.
At Cornell, where the basketball team recently made headlines, these results could have an even more dramatic effect.
“You would probably expect [the inherent racial bias] even more in a college setting because of the degree to which people monitor college referees is much less than in the NBA,” Price predicted.