OFF-SEASON drama in North America’s National Basketball Association (NBA) reached high gear on July 6th, when teams officially became able to sign free agents. Among the most momentous transactions so far has been the Oklahoma City Thunder’s acquisition of Paul George, a star small forward. Between him and Russell Westbrook, the league’s reigning Most Valuable Player, the team will present a formidable threat next year.

Mr Westbrook needs the help. Last season he achieved an extraordinary statistical feat. Basketball′s standard benchmark of virtuoso versatility is the “triple-double”: a game in which a player reaches double figures (ten or more) in three separate categories, usually points, rebounds and assists. Mr Westbrook managed to average a triple-double for an entire 82-game season. Only one player had ever done so before, all the way back in 1961-62.

Nonetheless, despite this Titanic accomplishment, the Thunder were easily eliminated in the first round of the playoffs. It is hard to reconcile Mr Westbrook′s magnificent handiwork with his club′s lacklustre showing. But one plausible explanation is that Mr Westbrook may have focused more on maximising his own glory than on winning games.

There is of course no way to know exactly what motivated Mr Westbrook. However, the overall pattern of players’ behaviour provides ample grounds for suspicion. Compiling large statistical totals is difficult, so it stands to reason that games with lots of rebounds or assists are rarer than those with just a few. For the league as a whole, the distributions match the expected pattern: there are fewer games with nine rebounds or assists than with eight, fewer with eight than with seven, and so on.

Among players on the brink of a triple-double, however, there is a conspicuous discrepancy. Players who already have at least ten points and assists are more likely to finish a game with ten rebounds than with nine. Similarly, those who already have at least ten points and rebounds are nearly as likely to wind up with ten assists as with nine. The comparative dearth of games with eight or nine assists or rebounds, and surfeit of those with exactly ten, strongly suggests that players with the opportunity for a triple-double change their actions on the court in order to attain one. Their teammates, aware of the glory that a triple-double can bring, may also help things along. These adjustments suggest such players are distracted from playing to win.

It is possible that Mr Westbrook is an exception to this pattern, and never took his eyes off the prize of victory. But if he was indeed guilty of “stat-padding”, next year is likely to be different. Now that he has matched the record, he may be less motivated to do so again. And Mr George’s arrival should make the Thunder a much stronger team. That will give Mr Westbrook a credible chance to play for a title, instead of mere individual renown.