In 2006-07 the Dallas Mavericks – led by league MVP Dirk Nowitzki — posted the best mark in the NBA with 67 victories. And then they met the Golden State Warriors in the first round and the dream came to a very quick end.
In the summer of 2007 the Mavericks made very few changes. But with essentially the same roster, the team declined last season. After 53 games the team’s record stood at 35-18. This is certainly a respectable mark, but a pace to win 54 games is quite a letdown after what the Mavericks and their fans saw two years ago.
The letdown inspired the decision-makers in Dallas to take action. In an effort to return to the top of the Western Conference and the NBA, the Mavericks traded Devin Harris, DeSagana Diop, Trenton Hassell, Keith Van Horn, Maurice Ager (along with draft picks and cash) to the New Jersey Nets for Jason Kidd, Malik Allen, and Antoine Wright. The key players in this transaction were Harris, Diop, and Kidd. Essentially the Mavericks were sending their starting point guard and a productive big man to the Nets for Jason Kidd.
As noted at the time, this trade should have helped the team (see Can Kidd Save Dallas?). But after Kidd joined the roster, the Mavericks posted a record of 16-13. And then in the first round of the playoffs the team was defeated in five games by the New Orleans Hornets. Such results clearly indicate that the Kidd acquisition didn’t help. Or does it?
Wins vs. Efficiency Differential
In evaluating the quality of a team we tend to look at wins and losses. After all, the object of the game is to win. Certainly teams that win more must be better than those that lose (or win less often).
Those that look at statistics and the NBA, though, have a different perspective. Although wins are often a very good measure of team quality, a team’s efficiency differential – offensive efficiency minus defensive efficiency – is a better predictor of future success (an example of this point is my discussion of the NBA Finals last June).
What does efficiency differential tell us about the Kidd acquisition? At the time of the trade Dallas had a differential of 4.3. When the season ended, the team’s differential stood at 4.9. For a team to increase its differential from 4.3 to 4.9 in just 29 games, that team would have to post a mark of 6.0 in the final games of the campaign. In other words, the Mavericks clearly improved after Kidd came to town.
Yes, the Mavericks were again losers in the first round. But remember, the Hornets had home court advantage in this series. And the Hornets posted a differential of 5.7 last season. In sum, these teams were not that different. In such a situation, it’s not surprising to see the team with home court advantage win.
The Nowitzki Story
We can see the Mavericks improved after the trade. But why exactly did they decline in the first place?
A few days ago I posted a story on the decline of the Philadelphia 76ers in 1983-84. In this column I argued that the key event was the drop-off in the performance of the team’s leading Wins Producer, Moses Malone. Although Malone was a top ten player in both 1982-83 and 1983-84, the difference in the former and latter season was still eight wins. And such a difference was a substantial part of the team’s overall decline.
A similar story actually played out in Dallas in 2007-08. Just before Christmas I wrote the following column about Dirk Nowitzki and the Dallas Mavericks:
This post indicated that the problems in Dallas could be linked almost entirely to the play of Nowitzki. And with respect to Nowitzki, most of the problem was a decline in his shooting efficiency (specifically his performance from beyond the three point arc).
Now let’s look at what happened after Kidd arrived:
Table One: Dirk Nowitzki, before and after Kidd
Table One reports Nowitzki’s stats before the acquisition of Kidd, after Kidd came to town, as well as what he did during the entire 2007-08 and 2006-07 campaigns. The numbers clearly indicate that Nowitzki’s performance improved after Kidd came to town. His adjusted field goal percentage increased from 49.2% to 54.6% (and his performance from three-point range improved from 29.1% to 48.1%).
When we turn to Win Score per 48 minutes, we see that Nowitzki posted a 16.2 mark in 2006-07. Before Kidd came to town, Nowitzki’s mark was only 14.1. Again, this is above average, but not quite what he was when he was named MVP. With Kidd on board, Nowitzki’s mark rose to 16.3. In sum, the numbers indicate the acquisition of Kidd solved the primary problem in Dallas. Nowitzki was able to return to his MVP form.
The Mavericks in 2007-08 and going forward
So if you’re a Dallas fan, the numbers I have reviewed might give you optimism for 2008-09. And if you look at the following numbers, your optimism might grow even further.
Table Two: The Dallas Mavericks in 2007-08
From Table Two we see that the Mavericks have the following above average players returning in 2008-09: Nowitzki, Kidd, Eric Dampier, Josh Howard, and Jason Terry. Diop has also returned to the fold. Such a collection does suggest this team could be quite formidable. But there are two factors that might prevent this team from winning its first title in 2009:
1. Kidd is old. Kidd entered in the league in 1994. Glenn Robinson – the first player chosen in that draft – last started a game in 2004. Like Robinson, most of the other players from that draft are not in the league anymore. The few that remain are no longer counted on to produce significant quantities of wins for their current employer. Kidd, though, must produce for Dallas to seriously contend. Although Kidd was very productive last year – producing at a level in Dallas that was quite similar to what he did in New Jersey in 2006-07 – we know this production cannot continue forever. At some point, Kidd’s production must decline. If that happens in 2008-09, then Dallas will have problems.
2. Even if Kidd doesn’t decline, the Mavericks have a bigger problem. The LA Lakers are an incredibly good team. Even if everyone on Dallas maintains his production levels from 2007-08, I don’t think this team is better than the Lakers (or the Celtics).
In sum, I think the numbers tell us the Kidd move made this team better. But I think the numbers we see in LA (and Boston) tell us that Dallas is not likely to win a title in 2009.
– DJ
The WoW Journal Comments Policy
Our research on the NBA was summarized HERE.
The Technical Notes at wagesofwins.com provides substantially more information on the published research behind Wins Produced and Win Score
Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:
Simple Models of Player Performance
What Wins Produced Says and What It Does Not Say
Introducing PAWSmin — and a Defense of Box Score Statistics
Finally, A Guide to Evaluating Models contains useful hints on how to interpret and evaluate statistical models.
Wages of Wins Journal 
Rashad
September 24, 2008
What, no celebratory post about the Mat Millen firing?
HKL
September 25, 2008
There is a bull case to be made that 53 is too low of a projection. You have to play the “ifs and buts” game a little. But, IF Dirk plays like he did post trade, there is an increase of 3.5 games. Diop only played 894 minutes. IF Dallas plays either Diop or Dampier 40 minutes per game, there is another 3 games. Kidd only played 1011 minutes. IF he only doubles that you can add another 5 Wins Produced (8 minus the 3 Harris got). That is 11 extra Wins Produced without making any unreasonable assumptions. Now, Howard played worse after the Kidd trade and Jones and Stackhouse got a year older, so maybe you have to temper that a little. You are also introducing a new coaching system. But my read of you numbers says this could be a 60 win team. No?
dberri
September 25, 2008
Rashad,
I will comment on Millen, but I thought I should say something more than “Hooray”.
HKL,
You are right, this could be a 60 win team (if Kidd keeps playing well).
Italian Stallion
September 25, 2008
I am a huge fan of point differential, but I believe there are less tangible qualities that sometimes determine wins and losses in very tight games. If anything, Dallas tends to be the type of team that does NOT perform well against other top teams under extreme pressure. I think unless Kidd can also overcome some of the psychological limitations of his team mates, Dallas will wind up with an attarctive point differential (earned against weak teams) but a disappointing record again.
Vince Gagliano
September 25, 2008
Speaking of the Lakers, one factor that we aren’t considering is Kobe’s pinky.
He’s adjusted quite well to a torn ligament, but if he were aggrevate it and lose three months of the season, things get a little bit trickier.
While he isn’t the most productive player by Win Scores, he is the most productive shooting guard the league. Replacing him with an average player at his position for three months could case L.A. to lose about 4 or 5 wins in productivity. And that could give some Western Conference teams (particularly the Hornets), some leverage in the playoff race.
And with so many productive players coming onto the team at one time, they run the risk of getting in each others’ way.
With the 2004 Lakers, Shaq’s scoring production dipped from 27.5 to 21.5, Kobe’s from 30.0, 6.9, and 5.9 to 24, 5.5, and 5.1, Karl Malone’s from 20.6, 7.8, and 4.7 to 13.2, 8.7, and 3.9, and Gary Payton’s from 19.6, 3.1, and 7.4 to 14.6, 4.2, and 5.5.
I get the feeling that the same affect to going to happen to the Lakers this year. After all, there’s only one basketball.
Alex
September 25, 2008
What I don’t understand is how a team with a 6.0 efficiency differential (during the 29 games with Kidd) could have a record of 16-13?!
I presume their expected win-loss record during that time would be a lot higher. Is there some reason the team seriously underperformed its expected record?
Italian Stallion
September 25, 2008
Alex,
That’s the point I was trying to address. IMO there are psychological aspects to all competitive sports/games. It’s not unusual to find some athletes that perform extremely well when facing inferior opposition because they are relaxed and feel no pressure. However, they tighten up and decline when matched against an equal or superior. So it is certainly possible that a team like Dallas could blow out all their inferior opponents but lose a lot of close decisions against similar competition when they should be winning more of them. The net result would be a large differential, but mediocre win/loss record.
Italian Stallion
September 25, 2008
Vince,
I’d love to see some studies done on dimishing returns. A more extreme example of what you are talking about was probably revealed by the US Olympic team stats.
Jason J
September 25, 2008
Surprising results, and according to every statistician I’ve read differencial is definitely a bigger factor in projected success than straight-up win / loss numbers.
Probably more than aging, I would be concerned about making projections with the new coach coming in. In a lot of ways Avery and Carlisle are similar – both like controlled tempo and defensive focus – but Avery was very familiar with everybody except Kidd.
It will be interesting to see if Rick is willing to play to Kidd’s strengths and open things up a little. If he does it should only benefit Dirk and hopefully (for Mavs fans) increased production for him really will be the key to better team success.
jones
September 25, 2008
if the hornets beat the mavericks in seven games, than yes, home-court advantage could be used. but the series was not close. the hornets dominated that series and the mavericks looked like they did not deserve to be on the same court as the hornets. home-court advantage is a pretty weak cop-out there.
Mountain
September 25, 2008
On the point Alex and Italian Stallion were developing I do think that different players perform at different ratios versus good teams compared to weak ones and that is significant and not well-revealed in public discussion.
I don’t know off hand what that ratio is for an average player but hoopsstats.com does report the crude / old NBA efficiency metric by various splits including vs .500+ teams and under .500 teams. Looking at Kidd he gets about the same NBA efficiency rating against either set but I see that every year but one in his career his unadjusted FG% is worse against above .500 teams. Sometimes by 2-3 % points, sometimes by 5, which would cost team only about 1 point per game and that is fairly big but not big enough alone to account for the team’s underperformance of point differential I don’t think.
Obviously small sample is a factor and makes randomness an issue as is the preformance against better by other players.
ON WP this FG% decline against better teams would have a far bigger impact on the rating and it could be respectably assumed this has ripple effects on team performance as a whole is Kidd is less effective at shooting.
As I said I don’t now what the average ratio is in the league but that could be calculated if anyone were sufficiently motivated to do a comprehensive survey or sample estimate.
Of course this doesn’t get to team performance or player adjusted +/- performance against good/weak teams but that conceivably could be done too. If anyone had the time and was willing to share.
It would be very helpful if 82games produced split pages like this http://www.82games.com/0708/0708DAL4.HTM
for players as well as teams but understandably they probably save that for their consulting sponsor team.
Mountain
September 25, 2008
Player and team defense against good/weak teams would be another split deserving more attention.
Dallas for season as whole was not in elite 6 on record against top 10 teams last season and the playoffs confirmed that. So 50 whatever wins in regular season matters to those who care about regular season records. Ultimately playoff success is based on performance in the subset against the best.
In 06-07 Dallas was exceeded on this measure by only 2 teams (Spurs, Jazz) but they weren’t at the same level at all. In 05-06 Dallas was very top for regular season performance against the best 10. In 04-05 they were third.
I think performance against top 10 in regular season is probably I pretty good guide for what will happen in playoffs but haven’t documented that carefully and of course the impact of conference schedules and specific playoff matchups and randomness will have their role too so these unadjusted numbers are loose guides needing interpretation or formal adjustment.
Mountain
September 25, 2008
Mavs best playoff performance in 2006 was after they had their league leading / recent franchise best regular season performance against top 10- 30-20 compared to 15-19 this past season.
Pistons and Heat title years only 2 of last 6 where champ wasn’t in top 2 in regular season performance against top 10.
Mountain
September 25, 2008
If you go for the big trade trying to get over the top might be best to choose players particularly strong against good teams.
One measure is playoff/ regular season performance ratio in a table produced by Mike Goodman. On this, Kidd has a similar ratio to Ray Allen (little drop-off in playoffs) while Gasol ranks a good deal lower- but not that much different than Rasheed Wallace who contributed to one and probably only one title.
Rashard Lewis ranks even lower. That acquisition was questionable for this reason beyond the outrageous price paid and the consequential pending probable loss of Turkoglu after this season.
The star on this short list of recent contender acquisitions – at least on this measure? Artest. 64th best all time in stepping up in playoffs. A good mark for the Rockets that I assume played a big part in the gamble.
Maggette actually #7. Spurs were perhaps rightly interested despite the reputation but didnt have enough money. Tim Thomas #19. Maybe somebody goes after him. Maybe the Spurs?
Of course regular season performance level base matters and playoff/ regular season is not the only relevant number.
Evan
September 25, 2008
Looking at Kidd he gets about the same NBA efficiency rating against either set but I see that every year but one in his career his unadjusted FG% is worse against above .500 teams.
Uh… I think you’d have to come up with a deviation from average for this to mean anything. I would expect that people would shoot better against sub500 teams. That’s common sense.
Christopher
September 25, 2008
3 thoughts:
1. I like the WOW paradigm of evaluating players. But this type of analysis highlights a flaw. Kidd was brought in to “get the Mavs over the hump”. The Mavs were not looking at a long-term frequency interpretation of what they _should_ win but rather at advancing in the playoffs. In other words, the flaw in the paradigm is that ultimate success is advancing through the playoffs and not compiling a high point differential. To wit, the Mavs would have gone as far with D. Harris as they did with J Kidd. Now they have cap issues and an old PG…
2 Kidd is old, his stats will decline. I’d love to see some notion of relative effectiveness as a function of age. By example, if PGs peak at age 27 what percentage of peak performance do they achieve on average from ages 22 – 34. I’d love to see that curve.
3 Sample size. I’m just not convinced that the improvement in efficiency is anything more that small sample variability. What is n here? Revisit this at the next All-Star break maybe?
In the end, I’d be surprised if the Mavs are still not a playoff team destined for a first round exit. And that is not why Kidd was brought in.
Mountain
September 25, 2008
Agreed but I already noted that.
Mountain
September 25, 2008
To be clear, my last comment was in reference to Evan’s.
Creed
September 25, 2008
Well, the Mavericks beat the Grizzlies by 15, the Wolves by 16, the Nets by 20, the Knicks by 29, the Bobcats by 25, the Pacers by 19, the Heat by 25, and the Sonics by 16. Many of these were at home. They lost to New Orleans several times, the Spurs twice, the Lakers twice, Boston, Denver, Utah, Houston, and Portland. If you look and adjust for home court and who they played, you might find that the Mavs were actually worse.
Evan
September 25, 2008
You’re right, you did note it (and I didn’t see it til after I wrote what I wrote). But I still don’t see why you even mentioned it because it seems unlikely to be non-negligible.
Mountain
September 25, 2008
I mention it as a paper trail in search for answers and to give an opportunity for someone to chime in if they have studied that or wants to. And because it is another case in additIon to several at apbrmetrics and hardwoodparoyxism where performance in normal setting vs tougher opponent appears appropriate because Kidd’s differential appears to elevated in the partial season in Dallas though it could be mainly randomness in small samples.
Mountain
September 25, 2008
That is Kidd’s differential on FG%, only one aspect of his game. The importance of which in respect to other elements of the game though is an ongoing major debate.
HKL
September 25, 2008
I think the original article overstates the Mav’s mediocrity prior to the trade. Dallas had the second best record in the league against WC playoff teams before Harris got hurt. There was a stretch of 12 games from when Harris went out to when Kidd came in where the Mav’s didn’t play well. Then, as has been pointed out, Dallas beat up the weak sisters and took 9 tries before they even beat a .500 team once Kidd arrived. It is probably a little tough to rely too much on point differential when you trade for a new PG late in the season and bring him into a team in turmoil. Good discussion!
rock
September 26, 2008
Congrats, you’ve done it again.
You have just proved why stats don’t mean sh*t. It’s all subjective.
Man of Steel
April 18, 2009
Well, here is a case where WP and Win Score seem to be demonstrably wrong about a given player. The article states that, even though the Mavericks won fewer games with Jason Kidd than they did before they had him, they were actually better then they had been previously because they had a higher efficiency differential. This is a somewhat plausible affirmation, since the sample size was extremely small (29 games; although this could be said to hold for efficiency differential as well, wins and losses are probably more variable than efficiency differential). However, this year the Mavericks are much closer to their pace last year after the trade than before it. So, contrary to the title of the article, Jason Kidd does not seem to have helped the Mavericks, “at least if the goal is to win games,” as is often said on this site. To wit, it seems that at this point, in spite of Kidd’s high productivity according to WP and Win Score, he has not helped the Mavericks than they would have if they had retained their previously assembled team.
This line of reasoning must be valid because it has been used frequently on this forum. Most of the articles about the Allen Iverson trade have focused on the fact that the Sixers were better after trading him than they were with him, and the nuggets did not improve as expected. If this line of reasoning works for Allen Iverson, then doesn’t it apply to Jason Kidd as well? The only difference has to rely on circular reasoning (i.e., Jason Kidd is proclaimed to be a great player by WP and Win Score, so his greatness is indisputable regardless of whether he helps his team win games or not. Allen Iverson, on the other hand, is proclaimed as a great player by popular opinion [or ppg, or whatever], an inferior measure, and thus he is not actually great if he does not help his team win games). This kind of argument does not seem to be very helpful. Again, in the language of this site, if the goal is to help ones’ team win games, then Jason Kidd is not the best player in the NBA (as he has been for several years according to Dr. berri’s metrics).