20 Second Timeout

If Some of the Numbers are Bogus Then How "Advanced" are "Advanced Stats"?

I have always enjoyed crunching numbers and looking at sports statistics, so I certainly am not some kind of anti-stat Luddite. I am not opposed to using basketball statistics, whether they are "archaic" box score-style stats or the so-called "advanced" stats that have been touted by various "stat gurus"; what I am opposed to is the misuse of basketball statistics, when people either rely too heavily on numbers at the expense of actually watching games and/or do not understand the significance/meaning of certain statistics.

Most of the so-called "advanced stats" are based on taking box score numbers--points, shooting percentages, rebounds, assists, steals, blocked shots, turnovers--and assigning particular weights to each category and/or converting per game numbers into per minute numbers that are adjusted for "pace" (one exception to this is plus/minus, which simply tracks the point differential when a player is on the court and compares it to the point differential when he is not on the court). It should be obvious that even if the weighting formulas are perfect--which they most certainly are not--the "advanced" stats are only as reliable as the basic data that they use. Even excluding the possibility of deliberate bias and/or incompetence on the part of scorekeepers, it should be obvious that assists, steals, blocked shots, turnovers and rebounds are all somewhat subjective in nature, so no player's box score statistics are 100% accurate. That is one reason that I criticize the way that so many "stat gurus" present their player rankings without any mention of a margin for error. Of course, the reason that "stat gurus" shy away from doing this is that they have no way of calculating a margin for error because they don't have a way to quantify how reliable the boxscore numbers may be, nor do they want to seriously consider the possibility that the weightings that they assign to those numbers may be less than perfect; if your "stat guru" competitor does not provide a margin for error but you do then in the court of public opinion you may appear to be less authoritative. I have no doubt that many teams use statistical analysis to some degree when making various decisions but you can bet that the data that they are using is more complete--and more focused on team comparisons as opposed to individual player rankings--than the information that various "stat gurus" are peddling on the open market in various books/websites. Also, many "stat gurus" seem to have thinly veiled agendas pertaining to how the game "should" be played, which kinds of players (guards or big men, rebounders or scorers, "high volume" players who are not "efficient" or "low volume" player who are "efficient," etc.) are most valuable and how competent (or, to be more precise, incompetent) they consider NBA GMs, coaches and scouts to be.

I have done several posts in which I provided detailed, play by play analysis of scorekeeping errors regarding assists. The last time that I charted assists in this fashion, 14 of the 16 assists credited to Chris Paul and Tony Parker fit the rulebook definition of an assist*. The Spurs lost 90-86 in New Orleans on Sunday night and those two players once again combined for 16 official assists (nine for Paul, seven for Parker). Here is how I would have scored those 16 plays:

Chris Paul's Nine Assists

1: David West jump shot, 9:01 1st q: Correct; this was a bit of a borderline play but I will give Paul the benefit of the doubt. West caught the ball, made a slight jab step and then went right up with the shot. It was not a straightforward catch and shoot but only about two-three seconds elapsed between the catch and the shot going up.

2: David West fadeaway jump shot, 5:22 1st q: Correct; this was also a bit of a borderline play where I am giving Paul the benefit of the doubt. West caught the ball on the left block and shot a turnaround jumper over Drew Gooden. West did not put on a whole low post clinic prior to the shot--as I have seen him do on some plays that were scored as assists for Paul (see next entry)--and he did go up for the shot pretty quickly after receiving the ball but it is hard to argue that the pass created the shot in the way that an alley oop lob or a drive and kick pass does. If this kind of pass is regularly scored as an assist then virtually every pass into the post--indeed, every pass preceding a successful shot attempt--would have to be deemed to be an assist.

3: David West jump shot, 4:41 1st q: Incorrect; this play is an egregious example of why I started charting assists in the first place and why I am inclined to consider this stat to be devalued to the point of almost being meaningless. Paul passed the ball to West at the top of the key at the 4:48 mark. West made a jab step with his right leg, then he pump faked, then he took one dribble and made a hard drive to his right before stopping and spinning to his left. The assist should already be well off the table by now but there is more. After coming to a stop, West pump faked again, did the "up" part of an up and under move but faded backwards instead of under, launching a one handed, high arcing shot over Drew Gooden. As Mike Tirico said, West"goes through the full arsenal of moves." Hubie Brown added, "That was a very pretty move. He gave Gooden at least three different moves off a jab step series and then caught him on a reverse move." Brown should have passed that comment along in a note to the official scorekeeper, because when a shot is preceded by enough post moves to be featured as a clip on an instructional video, there is no possible way that an assist should be awarded. You know what Chris Paul was doing while West was channeling Kevin McHale? He was standing well behind the three point line, watching, just like I was at home. The next time ESPN declares that Paul has broken an assist record set by Oscar Robertson, please remember this play.

4: David West jump shot, 4:21 1st q: Correct; after a screen/roll play, Paul fed West for a catch and shoot jumper.

5: Antonio Daniels three pointer, 1:59 2nd q: Correct; Paul posted up (!), drew a double team and kicked the ball out to Daniels for a catch and shoot. This is a perfect example of what an assist should be: Paul created a scoring opportunity for a teammate by drawing the double team and then he delivered the pass to the open man.

6: Julian Wright layup, 6:46 3rd q: Correct; Paul drove to the hoop, drew multiple defenders and passed to a cutting Wright, who scored a layup and was fouled, converting the three point play. This is another great example of an assist, because Paul created the scoring opportunity as opposed to simply making the last pass before a shot was attempted.

7: Julian Wright jump shot, 6:22 3rd q: Correct; once again, Paul attracted the defense and passed to Wright, who this time nailed a catch and shoot jumper. The difference between this play and assists one and two--which I consider to be correct but borderline--is that on the previous plays West was more closely guarded and had to do at least a little work prior to shooting (but he did make an immediate or close to immediate reaction to shoot and he did not put on a low post or perimeter footwork clinic) while on this play Wright simply caught and shot. The other nice aspect of this play is that Wright was open specifically because Paul attracted the attention of multiple defenders.

8: Julian Wright dunk, 6:42 4th q: Correct; Paul drew the defense and lofted a perfect alley oop to Wright, who was cutting to the hoop from the weak side. Wright pointed up in the air to signal to Paul, jumped off of two feet from just outside the restricted area and threw down a nice dunk.

9: David West jump shot, :38 4th q: Correct; this was a straightforward catch and shoot play.

Tony Parker's Seven Assists

1: Drew Gooden jump shot, 6:44 1st q: Incorrect; Gooden caught the ball on the right block at the 6:49 mark. He turned to face up his defender, made a strong drive and delivered what Hubie Brown called "a tough shot" over Hilton Armstrong. The issue is not the number of dribbles or time elapsed per se, but the fact that the assist had little to do with actually creating the scoring opportunity; it is not supposed to be the case that the pass immediately preceding a made basket is automatically deemed to be an assist.

2: Drew Gooden hook shot, 4:21 1st q: Incorrect; Gooden caught the ball on the wing, faked out a defender who was closing in on him, took two dribbles, turned 3/4 away from another defender and made a jump hook. Gooden created the shot with his one on one skills.

3: Manu Ginobili three pointer, :02 1st q: Correct; Parker drew the defense and passed to Ginobili, who immediately drained the shot.

4: Michael Finley three pointer, 5:57 3rd q: Correct; Parker drew the defense and passed to Finley, who nailed a three pointer with the shot clock running down.

5: Tim Duncan hook shot, 5:33 4th q: Correct; this is another borderline play. Parker caught the ball behind the three point line off of a back tap and fired a pass into Duncan in the paint. Duncan gathered himself with a quick dribble and a slight fake and then made a hook shot. I don't like the fact that Duncan made a bit of a one on one move before the shot but the whole sequence happened quickly and would not have been possible without Parker's bullet feed. I consider this play to be a judgment call. A "strict constructionist" might argue against awarding an assist because Duncan played a part in creating the shot but the nature of the pass--a quick feed deep into the post in heavy traffic--and the fact that it was a bang, bang play makes the awarding of an assist OK from my perspective. In contrast, if Duncan had performed multiple fakes and moves then I would be opposed to awarding an assist--even though it was a great pass--because in that case it could no longer be argued that the pass really created the scoring opportunity.

6: Matt Bonner three pointer, 3:40 4th q: Correct; just like assists three and four, this was a straightforward catch and shoot play.

7: Michael Finley three pointer, :17 4th q: Correct; this was another catch and shoot play.

Out of 16 assists credited to these two great point guards, 10 were unquestionably correct, three were unquestionably wrong and I have classified three as correct but borderline. I don't have a big issue with the borderline plays and I realize that there is some subjectivity inherent in this aspect of scorekeeping (even though there are some hard and fast rules outlining exactly what is and is not an assist) but the third assist awarded to Paul is indescribably bad scorekeeping by any standard. If the NBA is going to go back and take away one borderline rebound from LeBron James to nullify his triple double versus the Knicks then the league should certainly strike that assist from the record books.

It is worth noting that in this game Parker benefited more often than Paul did even though the game was played in New Orleans. I don't think that there is an NBA conspiracy or a New Orleans conspiracy involved with how assists are officially tracked; for whatever reason, scorekeepers are awarding assists more liberally than the rulebook says that they should. This would tend to favor players who are primarily playmakers--like Paul--but that does not mean that there is a deliberate effort to favor one player in particular. I have focused on Paul because he is the league leader, so I know that if I track him for a whole game that there will probably be a lot of plays to consider; in this post and my previous one on this subject, I also charted Parker as a "control" to see if only Paul is being credited with dubious assists.

I have now charted assists for Chris Paul in two playoff games and three regular season games; in the last two regular season games that I examined, I also charted Tony Parker's assists. The overall count in those five games shows that Paul was officially credited with 55 assists but that only 42 of those assists fit the rulebook definition (and those 42 include some borderline plays). In the two games in which I tracked Parker's assists, he was credited with 11 assists but should only have been credited with eight. The sample size with Parker is obviously small but I think that 55 official assists for Paul is a diverse enough sample of plays from which to draw at least a preliminary conclusion that he is being credited with too many assists. Paul is averaging just a shade under 11 apg this season but if he is consistently being credited with too many assists at the rate that I have observed in this sampling then he is actually averaging about 8.4 apg. If what I have charted reflects a season or career long trend then this is quite significant. Again, as I stated above, I don't think that the NBA or the Hornets are necessarily deliberately doing this but any bending of the scorekeeping rules regarding assists will obviously benefit playmakers more than other players. During the whole LeBron James triple double controversy, the NBA claimed that it regularly reviews game films and adjusts statistics that are improperly awarded; this certainly should not have been news to James, because the NBA had previously taken a triple double away from him due to a questionable assist (April 1, 2006 versus Miami). If it is true that the NBA so thoroughly supervises all of its scorekeeping (and not just games involving triple doubles) then assist number three for Chris Paul from this game simply has to be rescinded.

I should not even have to add this last paragraph, but it is almost certain that someone will read this post and conclude that I either (1) don't watch Chris Paul enough to appreciate his greatness and/or (2) I "hate" Chris Paul. Last summer, I ranked Paul as the best point guard in the NBA and put Parker fourth on my list; my charting of bogus assists does not lower my opinion of either player, because I don't rank players based solely on numbers. The reason that I am charting assists in this fashion is that I am very disappointed that the NBA and the "stat gurus" apparently do not care at all about the inaccurate and inconsistent methods used by NBA scorekeepers who produce the official assist numbers that go in the record books and form the basis of so many player ranking formulas.

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*For those of you who have not read my previous posts on this subject and/or do not know what the rulebook definition of an assist is, here is a passage that was posted on NBA.com in 2002 (yes, that was seven years ago but the NBA has not announced any official changes in its scorekeeping procedures regarding assists 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 concluding words of my December 18, 2008 post are well worth repeating here:

The rule of thumb to keep in mind is that the pass is supposed to "directly" lead to a basket. Every fake, dribble and move that the recipient makes after getting the ball makes that "direct" connection more and more tenuous. If the recipient is running down court uncontested and his teammate passes him the ball, then the number of dribbles he takes is irrelevant: he is meeting no defensive resistance and he clearly would not have scored without receiving that pass--but if a player is running down court, receives a pass, does a crossover dribble to shake one defender and then twists and turns to lay the ball up over another defender, then the pass did not really "directly" lead to the score because the scorer did most of the work. If the scorer does most of the work then the passer should not receive credit for an assist.

Labels: Chris Paul, LeBron James, New Orleans Hornets, San Antonio Spurs, Tony Parker

posted by David Friedman @ 4:22 AM

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