The statistic I'm proposing is, what is the expected points scored on this possession when a player starts his usage, and what is the expected points scored on the possession when he ends it? The difference between those two is a measure of his offensive value for that usage.
Example: Chris Paul dribbles the ball up court, with everybody already set in a halfcourt stance. In this scenario, the Hornets score, let's say, 0.8 points per possession on average. (Lower than their typical points per possession because all the high-value transition points are eliminated.) He dribbles around, and locates David West open underneath the basket, and gets the ball to him, whereupon the Hornets expected scoring at this juncture is 1.5 points. (Not exactly 2.0 because maybe he geeks the dunk, gets fouled, or whatever.)
Let's suppose West actually does score the basket. The ledger for this possession is as follows:
Initial expected scoring: 0.8
Increment by Chris Paul: +0.7
Increment by David West: +0.5
Actual score: 2.0
Maybe what he's talking about is a little hard to envision. Picture a basketball video game where the ball changes color when it's very likely to become points. So, if it gets close to the rim on the fast break, it might get really red, or hot. On the other hand, if the ball-handler is double-teamed in the corner, maybe it would be blue, or cold. If a great shooter catches the ball in rhythm for a corner 3, it'd be red hot.
Basically, players would be rewarded for taking a cold ball situation, and making it hot.
In general, it would be very very tough to accurately hand out credit for the many different things players do.
For instance, if I'm Chauncey Billups, and overhear the other team plans to defend our first option a certain way, I might call an audible and do something totally different. In reality, I've done something potentially brilliant. But if a teammate doesn't understand what was happening, and screws up the play, all you'd see, most likely, was me dribbling around a lot. Which would not help my team.
That's a minor quibble, though. More to the point, the smart kids are learning more and more every day how to quantify what matters in hoops. As they learn, this strikes me as a smart framework to organize new knowledge. Instead of putting valuable new numbers into spreadsheets or lists, put them into a play.
As Tung explains near the end of this post, this framework can also lends itself to a new way to value certain crunch time plays. Shots that seem really big to fans -- a 3 to win Game 7 -- look like any old points in most systems. But here, they can be seen as momentous.