Your team is up three points, and the other team has the ball with just seconds remaining in the game. There’s long been debate over the proper course of action: should a team foul to preemptively stop a game-tying three, or play honest defense and pray the ball doesn’t find the net?
Jonathan Abrams of the New York Times set out to analyze the issue in detail, enlisting the help of Synergy Sports Technology and a number of NBA coaches:
According to an analysis provided by Synergy Sports Technology,
the situation presented itself 165 times in the last two N.B.A. seasons
with 10 seconds or less left on the game clock. The conclusion?
Although coaches debate the strategy of fouling intentionally, most
rarely do. Teams deliberately fouled in only 19 of those instances.
(One team tried to foul but was unable to because of ball movement.) No
team fouled with a second or less remaining.
Teams that deliberately fouled won 17 of the 19 games in regulation and
lost once. Teams won all 14 of the games in which they purposefully
fouled with five seconds or less to play. One game went to overtime,
and the team that fouled when leading in regulation won.
When teams chose not to foul, they won 128 games and lost 4 in
regulation, according to Synergy, which logs every N.B.A. game and
provides data to teams. Fourteen games went to overtime, and the teams
split the victories.
I find two things about this data to be fairly surprising. The first bit is that coaches only elected to employ the strategy 11.5% of the time. Doc Rivers is cited amongst the firm advocates of fouling when up three, but Rivers aside, the data seems to show that the tactic is either restricted to a few zealots or a conditional decisions. Considering the nature of the debate, I naturally assumed that the frequency of such fouls would be a bit higher.
The second bit is that fouling when up three and not fouling when up three produced comparable win rates, with not fouling taking a slight edge. The sample size is still awfully small, but preventative fouling doesn’t appear to have a profound an impact as previously thought. The difference between the two options is fairly negligible given this data.
Perhaps the best part of Abrams’ piece, though, is the indirect discussion between the NBA’s top coaches. Everyone from Gregg Popovich to Larry Brown to Nate McMillan weighs in, and it’s perhaps even more enlightening to know each coach’s preference than it is to know the general trends.