06-04-2009, 03:17 PM
Join Date: Jun 2008
Study reports Refs have biases
Researchers' NBA officiating study detects biases, but not necessarily the ones fans suspect
An academic study of NBA officiating found little to no evidence that referees favor teams from large media markets in the playoffs, a favorite conspiracy theory of skeptical fans.
But the same study found that NBA referees tend to favor home teams, teams trailing in a game and teams trailing in a playoff series.
The study, conducted by three economics researchers, fuels the perennial debate about the influence of NBA officials on games. It suggests that forces ranging from league executives to simple human psychology can influence calls in a measurable way -- though not always enough to affect a game's outcome.
The researchers looked at six seasons of turnover statistics. They used ones where referees wield relatively little influence, such as a bad pass or steal, as a "control" group, and compared them with ones where referees wield greater influence, such as traveling and offensive fouls.
The researchers found that each type of favoritism -- home, trailing in a game and trailing in a series -- resulted in a 5 to 10 percent advantage in "discretionary" turnovers, or ones over which referees have the most influence. The researchers do not attempt to explain what the percentages could mean in actual wins and losses.
Still, the study concludes that the detected referee biases, though probably unintentional, could increase the league's revenues through additional ticket sales and television appearances by reducing the number of blowout games and making televised games more compelling.
"We can say with fairly high confidence that the results are not just due to randomness or (statistical) noise, that even teams facing elimination have an additional advantage in these referee-based turnovers, discretionary turnovers," said Daniel F. Stone, assistant professor of economics at Oregon State University and one of the study's authors.
NBA executives condemned the study, which is dated March 2009 and has not been published in a scholarly journal, criticizing its methodology, tone and conclusions. The league, whose showcase event, the Finals, starts tonight with the Los Angeles Lakers hosting the Orlando Magic, rigorously monitors officiating and does not condone favoritism, said Joel Litvin, the NBA's president of league and basketball operations.
Litvin also dismissed the study's suggestion that fans influence referees' behavior, a finding that echoes those in research about European soccer. The basketball study finds that the home-team advantage in discretionary turnovers increases by 1 percent for every 1,000 people in attendance.
Based on that figure, when the Trail Blazers ranked third in the league in average home attendance last season at 20,524, they should have received more than a 5 percent advantage in discretionary-turnover calls over the 2005-06 season, when they were last in the league with 15,049.
Litvin responded that NBA officials are the best in the world, reaching the league through superior skill and imperviousness to criticism.
"I do believe, and I think it's the case," Litvin said, "that these people are, in fact, immune to the things that you and I would say are just human nature.