During the 2016-2017 NBA season, the Houston Rockets shot just over 40 three-pointers a game. That was a record at the time, but it didn’t last long. The next season, the Rockets shot more than 42 threes a game – a record that also lasted only one season. This past year, the Rockets broke their own record once again, shooting 45 threes a game.
The Rockets are forging a new frontier here, but their record-breaking shooting is an extreme example of a trend that’s transformed basketball: teams are shooting more three-pointers than ever before. Few people have explored this trend more deeply than Kirk Goldsberry, a professor of sports analytics at the University of Texas at Austin, and author of “SprawlBall: A Visual Tour of the New Era of the NBA.”
Goldsberry is a cartographer by training. He made maps for FEMA before turning his love of basketball into a new career focus. He says the data needed to evaluate and adjust shooting effectiveness for NBA players has been available for a while now.
“Every year, the NBA, as a whole, shoots about 200,000 times,” Goldsberry says. “The NBA started adding x/y coordinates to their shooting datasets about 20 years ago. For all those 200,000 shots, we know who took it, where they took it and whether it went in. In the hands of a cartographer that is a treasure-trove of information.”
Goldsberry says basketball coaches can use shooting data to understand “the economic landscape of the court.”
An average three-point shot is obviously worth more than a typical six-foot shot that yields two points. But beyond that basic difference, Goldsberry says, different areas of the court have different average values.
“The first few feet behind the three-point line, you’re talking about an average value of about 1.1 points per shot,” Goldsberry says. “And in the two-point jump shooting areas, those non-paint, two-point jump shots – those are, in general, worth 0.8 points. It’s essentially a resource allocation issue.”
Goldsberry summarizes the challenge as first getting to know the terrain of the court, then evaluating individual players’ ability to score. “And then you put your players in the right places to thrive,” he says.
The term “SprawlBall” comes from Goldsberry’s geography background.
“Sprawl is a geographic term that sort of expresses the suburban growth of an urban area,” Goldsberry says. “That similar thing is happening in the NBA. As the three-point shot has become more and more popular, the game itself – the aesthetic of the sport – has sprawled out to the perimeter.”
Written by Shelly Brisbin.