Looking at the Best

Posted on April 2, 2007 by

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If we look at the standings one team stands alone. The Dallas Mavericks are the only team to win 60 games this season and currently – despite the loss to the Phoenix Suns yesterday – are still six games better than the Suns.

When we look at offensive and defensive efficiency, though, the Mavericks do not stand alone. After 72 games (which does not include Sunday’s action), the Mavericks had scored 108.9 points per 100 possessions while surrendering only 100.2 points. So the Mavericks efficiency differential stood at 8.7. Meanwhile, the Suns had an efficiency differential of 7.2, scoring 110.9 points per 100 possessions while surrendering 103.7.

And then there are the San Antonio Spurs. Despite having the worst record of the three, the Spurs have the best efficiency differential. Per 100 possessions the Spurs score 106.1 points while only surrendering 96.4. This results in an efficiency differential of 9.7.

As I noted a few weeks ago, no other NBA team comes close to this trio. Certainly we should expect the Western Conference champion, and eventual NBA champion, to come from these three.

Evaluating the Best

Looking at these teams one might wonder: Why are these three teams so good?

The answer is in the players. And to evaluate the players, we turn to the Wins Produced of the players on each team.

Table One: The San Antonio Spurs after 72 games

Table Two: The Dallas Mavericks after 72 games

Table Three: The Phoenix Suns after 72 games

The Wins Produced algorithm simply takes what we know about a team’s offensive and defensive efficiency and applies it to the evaluation of players. As a result, if offensive and defensive efficiency indicates that a team should win 57 games, this is what Wins Produced will indicate as well. In other words, it should not surprise us to see that as offensive and defensive efficiency indicates, Wins Produced tells us that the Spurs are currently the “best” team in the NBA (a point I will weasel out of at the end).

Looking at these teams via the lens of Wins Produced, we see that each of these teams has a few outstanding players, and a collection of less than outstanding players. The Spurs are led by Tim Duncan, Manu Ginobili, Tony Parker, and Brent Barry. These four players have combined to produce 48.5 of the 57.2 wins this team’s players have produced. In other words, once we get past these four, the Spurs suddenly look like a fairly bad team.

The same story can be told of the Mavericks and Suns. The Mavericks are led by Dirk Nowitzki, Jason Terry, Josh Howard, and Erick Dampier. These four have produced 45.1 wins, or all but 10 of this team’s Wins Produced. On the Suns we see Steve Nash, Shawn Marion, and Amare Stoudemire. These three players have produced 43.1 wins, or again, all but 10 wins on the Suns.

Each of the eleven players I listed has produced at least 0.180 wins per 48 minutes played [WP48]. Given that an average WP48 is 0.100, all of these players are very good and the key to the success these teams have achieved.

Once you get past these eleven, though, there isn’t much depth. The Spurs have no other above average players in their regular rotation. The Suns have only Leandro Barbosa and Kurt Thomas while the Mavericks can only offer Devin Harris and DeSagana Diop. Although these players are technically above average, none are far from the 0.100 mark.

Given that each team has a limited supply of “great players”, as is always the case in basketball, injuries can play a significant role in each team’s drive for a title. Injuries to any of the major producers identified can quickly derail each team’s playoff train.

The Impact of Regular Season Time

Another issue we might consider is minutes played. Erick Eschker and I, in a paper we published last year (which was cited in The Wages of Wins), found that the more minutes you played per game in the regular season the worse your playoff performance. The effect is small, yet statistically significant.

Let me ignore the “small” part of the story for a moment and pretend that all that mattered was statistical significance. Both the Mavericks and Suns are playing some of their major stars more than 35 minutes per night. Meanwhile, the Spurs are coasting in the regular season, playing only three players more than thirty minutes per contest (and none more than the 34.4 minutes played by Duncan).

This means that the Spurs will enter the playoffs as a lower seed than either Dallas or Phoenix, but will also be more rested. And come May and June, the well-rested Spurs might be in better shape to go the distance in a long playoff series.

At least, that is our story if we only consider statistical significance. Often I am seeing people post regression results on line that only consider whether the estimated coefficient is different from zero and ignoring the size of the coefficient. If a decision-maker is to use regression analysis to make choices, that person needs to consider both the statistical significance and the size of the impact. With respect to the link between minutes played and playoff performance, there is a significant relationship, but I do not think the size of the effect is so large that the Spurs truly have an advantage.

So Who is the Best?

In the end, the primary determinant of playoff performance is regular season productivity. And when it comes to these three teams we see that each employs several players that were very productive in the regular season.

Of course we want to know which team is the best. Unfortunately, I do not think there is an answer to that question (even if I said there was earlier in this column). All three are very good. At least two of these teams will not win an NBA championship this season. Although we might think the team that does win is indeed the “best” in the NBA, we know that the sample of games in the playoffs is insufficient to answer that question.

All that being said, if I had to pick a “best” team in the NBA I would have to pick…. the Detroit Pistons. And this is my pick because I was born in Detroit, and for me they are always the best team (as I said, I weaseled out of the question).

– DJ

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