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RandBall: Data ranks Wolves' Rubio, Love worst players in NBA last season

  • Blog Post by: Michael Rand
  • February 6, 2014 - 4:32 PM

A paper will be presented at the increasingly famous MIT Sloan Sports Analytics Conference later this month that summarizes methodology and early results from a new basketball statistic called Expected Possession Value.

One of the authors, Kirk Goldsberry, wrote about it on Grantland, and you can summarize it thusly: EPV seeks to place a value on every single movement of every single player every second they are on the court.

The abstract of the paper provides this:

"We propose a framework for using player-tracking data to assign a point value to each moment of a possession by computing how many points the offense is expected to score by the end of the possession, a quantity we call expected possession value (EPV). EPV allows analysts to evaluate every decision made during a  basketball game – whether it is to pass, dribble, or shoot – opening the door for a multitude of new metrics and analyses of basketball that quantify value in terms of points."

It is somewhere between fascinating and terrifying. We plan to write a little more about it for print tomorrow. Basically, as Goldsberry writes, "For years, we have talked about 'advanced stats' when what we were really talking about was slightly savvier arithmetic. That’s going to change, whether we want it to or not."

This could be the next revolution, and as it pertains to the 2012-13 Timberwolves and their two core players going forward, it is not pretty.

The number assigned to EPVA (EPV Added) amounts to the number of "points added" by a particular player in relation to an average player, as defined by what they do every time they touch the ball. Chris Paul has the best number, at 3.48. That means by being Chris Paul instead of an average player, he adds 3.48 points per game.

There were 327 players last season who had the requisite number of "qualifying possessions" to be charted. 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. (The top 10 and bottom 10 are located in one of the "tables" in that link.

Some 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 a largely ineffective and injury-marred season and is almost certainly much better in that number this year. As for Rubio? Well, as Goldsberry writes:

Rubio owes most of his “points lost” to his unfortunate shooting skills. Relative to league averages, he struggles to make shots in every part of the scoring area. 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.

Goldsberry doesn't claim EPV is the end-all, be-all statistic. Rather, he comes from a point of curiosity and love of data -- and he asserts that the contribution of EPV "remains unknown." We encourage you to read the entire Grantland piece if this all interests you.

But the methodology and sheer data involved are frightening in both scope and what they could mean for the Wolves' point guard. 

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