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Friday, November 01, 2013

Charting Chris Paul's Assists Versus the Golden State Warriors

On several occasions, I have charted the assists that have officially been credited to various players in order to determine how accurate the NBA's "official" assist totals are. Last night, Chris Paul authored a spectacular performance as his L.A. Clippers defeated the Golden State Warriors 126-115: Paul scored 42 points, dished off 15 assists and swiped six steals, becoming the first player to post 40-15-5 in those categories since the NBA began officially recording steals in the 1973-74 season--but did all of Paul's assists fit the strict rulebook requirements for an assist? It is no secret that NBA scorekeepers often employ a very liberal definition of an assist; here is the official description of an assist, as posted at NBA.com in 2002 (the rule has not changed since that time):

An assist is a pass that directly leads to a basket. This can be a pass to the low post that leads to a direct score, a long pass for a layup, a fast break pass to a teammate for a layup, and/or a pass that results in an open perimeter shot for a teammate. In basketball, an assist is awarded only if, in the judgement of the statistician, the last player's pass contributed directly to a made basket. An assist can be awarded for a basket scored after the ball has been dribbled if the player's pass led to the field goal being made.

The last sentence brings some subjectivity into the matter but old school scorekeepers would not award an assist on a play in which the recipient of the pass clearly did the bulk of the work to get open.

Here is my take on Chris Paul's 15 assists versus the Warriors:

1: Blake Griffin dribble drive, 11:02 1st Q: Correct, but borderline; Paul passed to Griffin, who received the ball at the free throw line, made a slight fake, took one dribble and scored. Griffin made an immediate attempt to score after catching the ball--so the assist has some validity--but the play could also be interpreted as a one on one move, not an assisted basket.

2: J.J. Redick fastbreak layup, 7:40 1st Q: Correct; Paul passed to Redick, who scored an uncontested fastbreak layup.

3: Blake Griffin drive, 6:07 1st Q: Incorrect; Paul passed to Griffin on the right wing and Griffin made a fake, took four dribbles and made another fake before scoring a layup. Giving Paul an assist on this kind of play is such ridiculously bad scorekeeping that it makes one question the validity of the assist statistic, because Paul had nothing whatsoever to do with Griffin scoring on the play. Griffin created the shot entirely for himself.

4: DeAndre Jordan dunk, 5:48 1st Q: Correct; Paul lobbed the ball to Jordan for the dunk.

5: Jared Dudley jumper, 5:13 1st Q: Correct; Paul fed Dudley for a catch and shoot jumper.

6: Blake Griffin jumper, 4:28 1st Q: Correct; Paul inbounded to Griffin, who held the ball briefly before nailing a jumper. A very strict scorekeeper might not award an assist because Griffin did not make an immediate attempt to score after receiving the pass.

7: Jared Dudley three pointer, 4:19 2nd Q: Correct; Paul passed to Dudley, who immediately fired away from long distance.

8: Jared Dudley fastbreak layup, 3:19 2nd Q: Correct; Paul fed Dudley, whose layup attempt was goaltended by Andre Iguodala.

9: J.J. Redick jumper, 1:44 2nd Q: Incorrect; Paul swung the ball to Redick, who used a pick and took two escape dribbles before nailing a tough, contested shot. Redick created the shot opportunity for himself, as opposed to the shot being created by Paul's pass.

10: Blake Griffin fastbreak dunk, 5:03 3rd Q: Correct; Paul lobbed the ball to Griffin for the dunk.

11: Blake Griffin fastbreak dunk, 4:47 3rd Q: Correct; Paul lobbed the ball to Griffin for the dunk.

12: Blake Griffin fastbreak dunk, 4:31 3rd Q: Correct; Paul lobbed the ball to Griffin for the dunk.

13: Jamal Crawford three pointer, 9:44 4th Q: Correct; Paul passed to Crawford for a catch and shoot jumper.

14: Jamal Crawford layup, 8:10 4th Q: Correct; Paul inbounded to Crawford for an uncontested layup.

15: J.J. Redick three pointer, 3:11 4th Q: Correct; Paul dished to Redick for a catch and shoot jumper.

Two of Paul's assists were incorrectly scored, one was a borderline case and the remaining 12 were clearly legitimate. This is the seventh time that I have charted Chris Paul's assists; in those games, he has been officially credited with 87 assists but only 70 of those assists comply with the rulebook definition--and that includes several borderline plays. Why does this matter? Assist totals are used by some commentators as a way to evaluate who are the league's best passers--and "stat gurus" use raw assist totals as part of their "advanced basketball statistics." Thus, if the raw assist totals are inflated/inaccurate, it is not appropriate to rank passers based on assist numbers and the "advanced basketball statistics" have to be taken with a grain of salt because the basic, raw statistics used to create the "advanced" numbers may not be correct.

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posted by David Friedman @ 4:38 PM

4 comments

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4 Comments:

At Friday, November 01, 2013 10:01:00 PM, Anonymous CR said...

Hey David,
Good work. Regardless of the accuracy of the totals, I think assists in general are overvalued. Can't a good screen be just as valuable as a good pass? But good screens are not tracked.

I also think too many "analysts" equate assists with unselfishness. If a player dominates the ball they are more likely to get high assist totals. Stephon Marbury used to rack up assist totals.

If a great scorer has a great matchup advantage it should not be considered selfish for that player to shoot more often in that game and maybe not have a very high assist total.

 
At Saturday, November 02, 2013 1:39:00 AM, Blogger David Friedman said...

CR:

I agree with you that assists are overvalued and that non-statistically quantified plays--such as screens--can be at least as valuable as the plays that are statistically quantified.

Your point about Marbury is right on target, as is your point about the value of a great scorer exploiting his matchup advantage by shooting the ball.

 
At Saturday, November 02, 2013 5:07:00 AM, Anonymous Nikola said...

Mar 11, 1958 Daily Boston Globe:

"How do you feel about the system throughout the league of scoring assists, if there is one set system?"

Cousy: "That's the trouble. I think there are eight systems. I think as I tell the boys in my Summer camp when they're scoring a game. Give an assist always to the last player to pass the ball to the man that scores, no matter how that final player scores."

For Cousy's and the Boston fans' benefit Dinny Whitmarsh, official scorer at the Garden, who, along with his WHDH partner, Sid Pike and Norman Altman, handle the "assists", describes just what is an assist.

Whitmarsh: "An assist is strictly a judgment call. You can't go by the book. A few years ago, Haskell Cohen, publicist of the N.B.A. told us scorers that we were giving out too many assists and suggested changes.

"Now, we do not give an assist if the player who last receives the ball, MAKES THE BASKET THROUGH HIS OWN EFFORTS AND NOT BECAUSE OF THE PASS. In other words, if Cousy passes to Bill Sharman, and Bill has to dribble a couple of times and go behind a "pick" and scores...no assist. No assist is given if the receiver fails in his initial goal try, but taps in a rebound. "In the case of Tommy Heinsohn, it's a bit different. Heinsohn may take a Cousy pass and then he usually makes a couple of moves or fakes, gets position for his hook and scores unaided...we give Cousy an assist."

 
At Saturday, November 02, 2013 6:38:00 PM, Anonymous Anonymous said...

Another fine piece of work,thanks.
I have often noticed some players are deliberately over lauded and statistic totals are skewed somewhat.

nimble

 

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