Just in time for conference championship week, The New York Times’ David Leonhardt interviewed University of Pennsylvania economist Justin Wolfers on the likelihood of point shaving in college hoops.
Mr. Wolfers (above) has collected the results of nearly every college basketball game over the last 16 years. In a surprisingly large number of them, it turns out that heavy favorites just miss covering the spread. He considered a number of other explanations, but he thinks there is only one that can explain the pattern. Point shaving appears to be occurring in about 5 percent of all games with large spreads.
Officials at the National Collegiate Athletic Association say they do not believe that the problem is nearly so large. Jay Kornegay, who oversees the betting lines at the Las Vegas Hilton, told me that Mr. Wolfers’s conclusions sounded “ludicrous.” But I’m not so sure about that.
When Mr. Wolfers began his research, he started with a question: If there were really a lot of point shaving going on, what sort of tracks would it leave in the data?
In all likelihood, the cheating would be concentrated among heavily favored teams. Point spreads require gamblers to bet on whether the favored team will win by at least a certain margin. By agreeing to fall short of that, players can fix a game and still not risk losing it.
“It’s the favorites with the big spreads,” Kenny White, an influential Las Vegas oddsmaker, said, “that have the biggest advantage to be able to do something.”
Past scandals also suggest that is how it works. When Stevin Smith was fixing games at Arizona State in the 1990’s to erase some big gambling debts, he hit some big shots and helped his team win games. But he backed off just a little on defense to make sure his opponents covered the spread.
“I made myself feel better by always saying that I wasn’t making my team lose, just helping myself out of a bad situation,” Mr. Smith later wrote in Sports Illustrated.
This is precisely the pattern Mr. Wolfers believes that he has found. Smaller favorites ” teams favored by 12 or fewer points ” beat the spread almost exactly 50 percent of the time, showing how good those oddsmakers are at their jobs. But heavy favorites cover in only 47 percent of their games. There is little chance that the difference is due to randomness.