By John Ezekowitz
Back in March, Maryland and Michigan State played one of the best final minutes of an NCAA Tournament game in recent memory. Down two points with a timeout left after a Greivis Vasquez layup, the Spartans pushed the ball up the floor, leading to this:
If you look closely, you can see Tom Izzo on the sidelines, about to signal for a timeout when he thinks better of it. This led the excellent John Gasaway of Basketball Prospectus to wonder “if teams actually do better in these situations [at the very end of games] without a timeout?”
Like the naive college student I am, I took on Gasaway’s challenge and decided to find out empirically. After many hours of work, I have compiled a database of every play from the 2009-2010 college basketball season in which a team had the chance to tie or win the game (ie down 3 points or less to tied), 1546 plays in all. In future posts, I will use this dataset to analyze the effectiveness of timeouts in various end-of-game situations, but would first like to present an appetizer on fouling when up three points.
To foul or not to foul? The debate about the efficacy of intentionally fouling has raged on in basketball circles for years. Recently, Luke Winn looked at the issue through the lens of the classic Kansas St-Xavier Sweet Sixteen game, and Henry Abbott at TrueHoop looked at the issue from an NBA point of view. Abbott cited hoops statistician Wayne Winston’s study of NBA games that found no significant advantage to fouling when up three points. My dataset presents, to my knowledge, the first comprehensive empirical study of the issue for college basketball.
In the 2009-2010 season, I found 443 instances where a team held the ball down three points during their last possession of a period (either the end of the 2nd half or an overtime period). In 391 of those cases, the team leading did not foul. In 52 cases, the team chose to foul. While the unequal sample sizes aren’t ideal, the 52 cases of fouling are significantly more than found in Winston’s NBA study (27).
Of the 52 teams that committed a foul, six lost the game for a winning percentage of 88.46%. Of the 391 teams that did not foul, 33 lost the game for a winning percentage of 91.56%. Both a two sample t-test of proportion and a Chi-squared test fail to reject the null hypothesis that there is a difference in winning percentage between the two strategies. In this sample, teams that did not foul won slightly more often. For the less statistically inclined, this means that there is no significant difference between the two strategies.
Another way to analyze the effectiveness of fouling is to look at how often the team that trailed scores at least three points (I say at least because of this epic case which I have highlighted previously). Because of the way my sample is constructed, the possessions in which a team trails by three points really are at the end of the game. A team that fails to score three points in my sample cannot win.
(Edit: In response to some issues raised by readers, I went back and re-ran the numbers. The conclusions did not change. The explanation follows below)
Here, too, the two strategies are almost identical. Interestingly, in eight cases, the leading team fouled the shooter in the act of shooting a 3-point shot (six of those times, the shooter made all three free throws) .Some of these cases, like the Kansas State, are players who are instructed to foul simply fouling too late. In others, the coach probably did not want an intentional foul while up three. I went back using game stories and video (where I could find it) for these eight cases and determined to the best of my ability that four of these cases were intentional, three were not, and one was unclear. To be conservative, I called the unclear case “not-intentional.”
Teams that intentionally foul allowed the opponent to score three seven times out of 48. Teams that did not allowed the opponent to score three points 93 out of 395 times. While teams that did intentionally foul gave up three points a smaller proportion of the time than teams that did, the difference was not statistically significant (p values of .067 and .113 for a two sample t-test and a Chi-squared test). That means that in 2009-2010, teams that were down three points at the end of the game scored the necessary points at rates that did not differ based on which strategy the leading team pursued.
(Edit: I just wanted to make this clear: in only 3 of 52 cases did a team miss the 2nd free throw, successfully get the offensive rebound, and score. In this data set, the reason that the intentional foul strategy is not significantly different from not fouling are the cases in which the team fouls a player in the act of shooting a three.)
While these results are certainly interesting and convincing, clearly there is further study to be done. While my study does not have a “time remaining” component, it does largely deal with Winston’s criticism of early studies, which did not account for the uncertain number of further possessions in the game. This is because the possessions analyzed here are the last ones where the team has a chance to tie the game.
I would love any thoughts or comments you might have on this work. Please stay tuned for the bulk of the research on the efficacy of timeouts.