NEW YORK -- An academic study of NBA officiating found that
white referees called fouls at a greater rate against black players
than against white players, The New York Times reported on its Web
site Tuesday night.
The study by a University of Pennsylvania assistant professor
and Cornell graduate student also found that black officials called
fouls more frequently against white players than black, but noted
that that tendency was not as pronounced.
Justin Wolfers, an assistant professor of business and public
policy at Penn's Wharton School, and Joseph Price, a Cornell
graduate student in economics, said the difference in calls "is
large enough that the probability of a team winning is noticeably
affected by the racial composition of the refereeing crew."
The study, conducted over a 13-season span through 2004, found
that the racial makeup of a three-man officiating crew affected
calls by up to 4½ percent.
The NBA strongly criticized the study, which was based on
information from publicly available box scores, which show only the
referees' names and contain no information about which official
made a call.
"The study that is cited in the New York Times article is
wrong," president of league and basketball operations Joel Litvin
told The Associated Press on Tuesday night. "The fact is there is
no evidence of racial bias in foul calls made by NBA officials and
that is based on a study conducted by our experts who looked at
data that was far more robust and current than the data relied upon
by Professor Wolfers.
"The short of it is Wolfers and Price only looked at calls made
by three-man crews. Our experts were able to analyze calls made by
individual referees."
Litvin said the NBA's study, using data from November 2004 to
January 2007, included some 148,000 calls and included which
official made each call. The Times said the NBA denied a request by
Wolfers and Price to obtain that information, citing its
confidentiality agreement with the officials.
The study also found differences in everything from a decrease
in scoring to a rise in turnovers depending on the officials' race.
"Player-performance appears to deteriorate at every margin when
officiated by a larger fraction of opposite-race referees,"
Wolfers and Price wrote.
But the key finding was in regard to foul calls, saying "black
players receive around 0.12-0.20 more fouls per 48 minutes played
[an increase of 2½-4½ percent] when the number of white referees
officiating a game increases from zero to three."
The NBA has an observer at each game and closely monitors its
officials, who are required to file reports after each game they
work and are expected to be able to explain each potentially
controversial call they have made.
Litvin said in an original version of the paper, dated March
2006, Wolfers and Price came to the conclusion that there was no
bias. He added that the NBA's research "all prove beyond any doubt
in our minds that these guys are just flat wrong."
"They reached conclusions in their own papers that are
unsupported by their own calculations," Litvin said.
Wolfers and Price are set to present the paper at meetings of
the Society of Labor Economists on Friday and the American Law and
Economics Association on Sunday. The Times said they will then
submit it to the National Bureau of Economic Research and for
formal peer review before consideration by an economic journal.