SAN ANTONIO — The most important play in a game isn’t always the one you remember most. Sometimes, it’s subtle and doesn’t even make the highlight reel. Sometimes, something as simple as a change in possession can be more important than a shot that does or doesn’t go in.
The NBA has a way to use analytics to figure out just which plays had the biggest impact on a close game. It’s a “leverage” model that was developed to evaluate and instruct referees by pointing out which calls or no-calls had the biggest impact on a game’s result.
Here’s the idea: At every point of a game, each team has a certain probability of winning. Putting the quality of each team to the side, when the game tips off, the home team has a 60 percent probability of winning and the road team has a 40 percent probability of winning. After the first basket, those numbers haven’t changed much. But if the home team is up 10 with the ball and five minutes to go in the fourth quarter, their win probability (WP) is obviously a lot greater than 60 percent.
So, by calculating win probability both before and after a play occurs, it can be determined just how important that play was. Score, possession and location are the factors. And obviously, plays in the last few minutes of the fourth quarter (or overtime) in a close game are more important than any others.
Using the league’s data model, we’ve determined the three most important plays of Game 4 of The Finals, a comfortable 109-93 win for the Miami Heat that evened the series at two games apiece
The Heat didn’t put the game away until they went on a 16-6 run midway through the fourth quarter, but the biggest plays of the night came before that, with the game still in the balance late in the third and early in the fourth.
3. +8.1 percent – Neal drains a 3
In the midst of scoring on 11 of their final 12 possessions of the third quarter, the Heat had a six point lead and looked to be taking control. But after a LeBron James miss in the post, the Spurs got the ball quickly up the floor. Ray Allen was able to get to Danny Green in the corner, but Green found a trailing Gary Neal, who (of course) didn’t hesitate to jack up a 3 that pulled San Antonio within three with 1:39 left in the period.
The 3 changed the Spurs’ WP from 31.3 percent to 39.4 percent.
2. +8.8 percent – Wade’s and-one
On the very next possession, the Heat’s first few options were well covered and Dwyane Wade had the ball in the corner. But when James slipped a corner screen, neither Green nor Manu Ginobili stayed with Wade, who drove, drew a foul on Green, and hit a tough bank shot as he was falling to the ground. He then converted the free throw to put the Heat back up six.
The play increased the Heat’s WP from 60.6 percent to 69.4 percent.
1. +12.6 percent – James’ steal leads to Allen’s trey
Miami’s lead was five in the first minute of the fourth quarter when Ginobili hit a rolling Tiago Splitter in the lane. As Splitter came down with the ball, he tried to kick it to Kawhi Leonard in the corner. But James, who had helped off Leonard, read Splitter’s mind and took the ball right out of his hands.
(James’ defensive anticipation was rather ridiculous all night.)
James raced up the floor, drew four Spurs defenders into the paint and got the ball to Norris Cole in the left corner. Cole was wide open, but spotted Allen on the wing. Leonard closed out on Allen, but a pump fake got him out of the way. Allen drained the 3 (one of only four the Heat made all night) to increase the lead to eight points.
Before James’ steal, the Heat’s WP was 67.6 percent. The change of possession increased it to 72.6 percent (+5.0) and the three made it 80.2 percent (+7.6).