By John Ezekowitz
After first writing about the decision to intentionally foul when up three, I’m continuing my analysis of the very end of close college basketball games by examining how calling a timeout affects whether or not a foul is called. Conventional basketball wisdom holds that fewer fouls will be called on the defense after a timeout because a coach can advise his players on how specifically to defend. Additionally, after a timeout the chance that the offense can break through and force an out-of-place defender to foul is greatly diminished. But does this conventional wisdom hold in the most pressure-filled possessions of a game, when a block/charge call can swing the outcome?
The answer, according to my dataset, is decidedly yes. Teams were much more likely to draw a foul if they did not call a timeout before that possession. Teams drew fouls on 13 percent of end-of-game possessions when they did not call a timeout. Teams that called a timeout only drew fouls on 8 percent of their possessions. This difference was strongly statistically significant (p=0.001). (Edit: as a commenter points out, I should mention that I did not include plays were the deficit was 3 points so as to avoid being biased by intentional fouls).
In this sample, the logistic regression with a foul as the dependent variable and calling a timeout as the explanatory variable showed that not calling a timeout increased the odds of a foul being called by 75 percent (note: the marginal effects (the 75%) may be an overestimation caused by the logistic regression, but the direction of the effects are clear).
A quick note on why fouls at the end of games are important: teams that were fouled in their last possession while trying to tie or win a game scored, on average, 1.62 points per possession. Teams that were not fouled only scored 0.878 ppp. That is almost twice as much. These numbers vary by situation (as I will get into more heavily later next week), but the fact remains: if you want to score points at the end of games, you are more likely to score more points more often from the foul line. The difference in drawing fouls certainly matters for the outcome of games.
But these numbers only present the beginning of the story. It would be interesting to see if calling a timeout diminishes the odds of a foul being called throughout the game, or whether the effect is greater at the end of close games. If the latter is the case, it may be that referees perceive higher leverage possessions at the end of games differently. Letting a team run when trying to win or tie the game may not only stop the defense from getting set: it may also may force a referee to make a different decision on a vital foul call.
There is certainly some evidence that refs call the very end of close games differently. According to my calculations based on Statsheet.com’s statistics, fouls were called on 27.35 percent of all possessions in college basketball last year. In my sample of over 1500 plays at the end of close games, fouls were only called on 13.95 percent of possessions. While I was unable to run hypothesis testing on this difference, the magnitude is striking. In 2009-2010, referees called fouls half as often at the end of close games. It would be extremely unlikely for this difference to happen simply by random chance.
Is this evidence that refs really do “let them play” more at the end of games? And if it is, is that something we as fans want? That is certainly a discussion worth having.
In addition to this issue, there is clearly a relationship between the calling of a timeout and drawing fouls at the end of close games. While these conclusions may not be earth-shattering, they do empirically back conventional wisdom. I think it is always valuable to test one’s assumptions. Further analysis is definitely needed, and I would love any thoughts readers might have on these issues.