Ref patterns don’t raise red flags

As NBA officials pore over refereeing statistics and game videos to ferret out signs of game-fixing by disgraced referee Tim Donaghy -- an effort NBA Commissioner David Stern said would consume “the fullness of the summer and the autumn” -- how likely are they to find a damning pattern?

A look at the statistics already available to the public suggests the odds are long.

Certainly no patterns caught the eye of betting analysts before the disclosure last week that Donaghy is being investigated by the FBI for betting on NBA games, including games at which he officiated. Sports book operators in Las Vegas say there were no signs of suspicious betting action in town over the last two years, the period for which Donaghy is under investigation.

“We didn’t have any discussions about that,” says Jay Kornegay, director of the sports book at the Las Vegas Hilton. Adds Steve Fezzik, a professional bettor who is a featured contributor to LVAsports.com, “This wasn’t on anybody’s radar screen.”

One reason may be that the NBA ranks relatively low in interest among Las Vegas bettors, who spend far more money on NFL and college basketball games. Las Vegas sports books seldom accept wagers of more than a few thousand dollars on an NBA game from any bettor.

Stern said this week that he was as yet unaware of any charges that Donaghy was involved in the “fixing of games,” as opposed to merely betting. Even attributing suspicious calls to any one referee would be difficult, as the NBA does not release statistics on individual refs’ in-game calls.

Instead, all fouls are attributed to each of the three referees assigned to that game. The three-man crews, moreover, are broken up and reassigned after every two or three games.

Stern said that the league has tried to sharpen its officiating in recent years by intensifying its postgame reviews of referees’ calls.

Nevertheless, the officiating performance varies greatly among the refs and season by season. For example, veteran ref Dick Bavetta produced a 41-41 record against the over-under points total in 2006-2007. The previous season his record was 46-37 -- a bit off Donaghy’s 36-30 record that season. Similarly, games refereed by Derrick Stafford were 31-32 against the over-under total last season, but 50-23 in 2005-06.

Still, several sports betting analysts have pointed to suspicious trends in games at which Donaghy officiated over the last two seasons. R.J. Bell, president of the sports information site pregame.com, contended in a column that Donaghy’s “on-court behavior the last two seasons has an over 95% probability of being abnormal.”

Bell based that conclusion on the unusually high game point totals, related to betting lines at Donaghy’s games.

Betting analysts say the point total is a key statistic in analyzing Donaghy’s performance because the most effective way for a referee to affect a basketball game is to whistle a lot of fouls, which will give players more free throws and drive up the combined score.

Bettors aware of this tendency can bet the “over” on an over-under play, meaning they will win if the two teams’ scores total is more than projected.

In 78 out of 138 games in which Donaghy officiated in the last two seasons, or 57.25% of the time, the total points exceeded the Las Vegas over-under line, according to covers.com and to pregame.com.

Still, that was not a unique performance; at least three other NBA refs had percentages similar or higher, including Jim Clark, whose two-year over-under record was 92-57, or 61.75%.

Pregame.com’s general manager of content, Matty O’Shea, says Donaghy’s pattern becomes clearer when matched against changes in the Las Vegas betting line before game time. Of the first 15 games refereed by Donaghy last season in which the betting point spread moved 1.5 points or more, he says, “the big-money gamblers won a perfect 15 of 15 times.”

He also notes that Donaghy refereed six games last season in which a big infusion of betting interest moved the line by more than three points -- and the late money won all six.

For all that, however, O’Shea agrees that it would be “very difficult” for the NBA to have spotted such a pattern in advance.

Some other experts say they are willing to accept the NBA’s assertions that it believes Donaghy to be an isolated case of betting or game-fixing, given that experienced NBA refs earn six-figure incomes; Donaghy, Stern said, earned $260,000 last year.

But they say that its experience should be a wake-up call for the NCAA, whose basketball referees are part-timers paid by the game. “What might be going on in college ball?” Fezzik asks. “You could just call lots of fouls and a game would go over [the betting line]. People would just say, ‘Hey, they’re calling it close tonight.’ ”

michael.hiltzik@latimes.com