DOES JOEY CRAWFORD HATE THE SPURS?
In March 2007 NBA official Joey Crawford ejected Spurs star Tim Duncan during a game against the Dallas Mavericks. The NBA then suspended Crawford for the rest of the 2007 season. They said that he “was unfair to the Spurs.” Is it possible to determine whether Joey Crawford's officiating harmed the Spurs' performance during Spurs games in which he officiated? If Joey Crawford was biased against the Spurs, then we would expect the Spurs to have played significantly worse than expected during the games in which Crawford officiated. To determine an expected level of performance by the Spurs, we looked at each Spurs game officiated by Crawford during the 2004–5, 2005–6, and 2006–7 seasons. Using the season-ending Sagarin ratings and a home edge of 3 points we made a prediction for the amount by which the Spurs should have won each game. Then we computed for each game
For example, on April 15, 2007, the Spurs played the Mavericks at Dallas. They lost by 5 points. The Spurs had a season- ending rating of + 8.54, while the Mavericks had a season- ending rating of + 6.96. Our prediction for this game would have been that the Spurs would win by (8.54 — 6.96) — 3 = —1.42 points, or the Mavericks win by 1.42 points. Therefore, the residual Spurs performance for this game= —5 — ( — 1.42) = —3.58 points.
Historically the standard deviation of game margins about predictions made using the season- ending Sagarin ratings is around 12 points. If Crawford adversely affected the Spurs' performance, then we would expect the average of the Spurs' residuals to be significantly negative.
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