The ESPN Series, Outside the Lines, conducted an investigation of the 2007 Betting Scandal where NBA Referee Tim Donaghy pleaded guilty to betting on games he officiated but it was never proven that he fixed games, until now.
In the original investigation, very few games were actually looked into. Former FBI Agent Phil Scala explained how there was push back, and executives were eager to move on from this case thinking it was impossible to fix games, to begin with, which Scala found to be ridiculous. While Donaghy admitted to betting on games as far back as 2003, the original investigation only analyzed 17 games Donaghy officiated in the 2006-2007 season. Reports from that investigation concluded that one of those games, Detroit Pistons versus New Jersey Nets on December 16, 2006, raised concerns as it looked like that game was favorable towards the Pistons which was the team Donaghy and his associates picked to cover. (And they did)
ESPN conducted it's own more complete analysis from the time Donaghy entered an agreement with his co-conspirators up until the day their scheme fell apart.
The video below shares their findings:
Of those 40 games, 10 of those games were blowouts and discarded from the analysis. In 23 three of the 30 games that were competitive, Tim Donaghy's calls favored the team that his partners wagered on. That's 77% and only three games that his calls went against his partners. The calls were even in the other four games. The odds of that imbalance occurring randomly is 6,155 to 1.