NBA Referee Bias: Do Statistics Suggest a Home Court Advantage? Is there Favoritism toward Teams Facing Elimination?

In the summer of 2007, former National Basketball Association (NBA) referee Tim Donaghy was found to have bet on games that he officiated. Donaghy subsequently alleged that referee bias is rampant throughout the league. The scandal created widespread speculation about the legitimacy of controversial games in recent history, though NBA Commissioner David Stern argued vehemently that Donaghy was an isolated individual in his deviance. In light of this contentious issue, this paper empirically investigates whether there is evidence of referee bias. Specifically, home bias and prolonged playoff series bias are examined through analysis of multiple statistical categories, including discretionary turnovers (DTOs) and non-discretionary turnovers (NTOs). To analyze prolon ged series bias, this study observes teams facing elimination (down 2-3, 1-3, or 0-3) as well as those threatening to eliminate (up 3-2, 3-1, or 3-0). In these “one-sided elimination games,” or “pre-game 7 elimination games,” only a win by the team trailing in the series can extend the series to an additional game, generating added league revenue from ticket and advertisement sales. So, if the data analysis suggests that particular statistics are significantly favored toward teams facing “one-sided elimination,” it may suggest prolonged series bias among referees.