If you’re an NBA fan who is just starting to get comfortable with stats like PER (Player Efficiency Rating), your world might soon be turned upside down.
Four Harvard statistics gurus will present a paper later this month at the MIT Sloan Sports Analytics Conference on a new basketball statistic called Expected Possession Value.
One of the authors, Kirk Goldsberry, wrote about it on Grantland.com. Basically, EPV seeks to quantify every movement of every player in every situation on the court — pass, dribble, fake, shot, you name it.
The amount of data is somewhere between fascinating and terrifying, as is the potential use of the results. It was first tested using information from the 2012-13 season, from cameras in 14 NBA arenas. Goldsberry writes that 800 million player locations were charted, resulting in nearly 100 gigabytes of data.
This year they are using data in every NBA arena. But the numbers we have to work with are from 2012-13 for now, and if you believe in EPV and the Timberwolves, this next part is going to hurt.
Players are measured using EPV Added — the number of points they add per game by being themselves instead of an average NBA player. This takes into account every action he performs with the ball. There were 327 players last season who had the requisite number of “qualifying possessions” to be charted.
Chris Paul was No. 1, at plus-3.48 points. The player with the worst EPVA of those 327 was Ricky Rubio, at minus-3.33. The player with the second-worst EPVA was Kevin Love, at minus-2.38.
Now: Other players we consider to be very good — Russell Westbrook and Paul George among them — were also in the bottom 10. And let’s remember that Love had an injury-marred season and is almost certainly much better in terms of EPVA this year.
As for Ricky? Love’s poor season hurt him, too, but mostly it was his shooting. “Relative to league averages, he struggles to make shots in every part of the scoring area,” Goldberry writes. “In terms of EPV ‘over replacement,’ almost every jumper Rubio decides to take is a proposition less valuable than if almost any other similar player took that exact same shot.”