If you follow the link you will hear Dan Patrick - now of Sports Illustrated - interview George Karl (hat tip to Andy Feinstein of Denver Stiffs - formally FireGeorgeKarl.com). In the course of this conversation Dan Patrick re-iterated a common critique of the Denver Nuggets: Denver doesn’t play defense.
Denver allowed 107 points per game, a mark that ranked 29th in a 30 team league. So it’s easy to see why people think Denver has problems on defense.
Denver is a “Good” Defensive Team
At least, it would be easy to see if you didn’t know one basic fact about basketball. Some teams play at a fast pace while others take it slow. This one basic fact means that to properly evaluate a team’s offense and defense we need to consider points scored and allowed per possession. In other words, we have to consider offensive efficiency and defensive efficiency.
The Nuggets average 103.1 possessions per game, which is the fastest pace in the NBA. Given this quantity of possessions, the Nuggets had a 103.7 defensive efficiency [(107.0 / 103.1)*100]. This mark ranks 12th in the 30 team NBA. In sum, Denver was actually an above average defensive team in 2007-08.
If you have read The Wages of Wins you have seen the argument that teams should be evaluated in terms of offensive and defensive efficiency. And such an argument is not unique to The Wages of Wins. It can be also found in the writings of John Hollinger and Dean Oliver. And I believe Oliver notes that this idea goes back decades. Yet apparently, it’s completely lost on Patrick.
Okay, Patrick is a sportswriter. Sometimes (as is often noted here), sportswriters get it wrong (see the vote for Kevin Durant for Rookies of the Year or Kobe Bryant for MVP). But what is truly amazing about the Patrick-Karl interview, is that after Patrick asserts that Denver is “bad” defensive team (where “bad” is defined as below average), Karl doesn’t disagree. One would think that Karl, who has to have heard that teams play at different speeds, would have quickly told Patrick that he was wrong. Once you adjust for pace, Denver is a “good” defensive team (where “good” is defined as above average). This, though, doesn’t happen. Is it possible that Karl doesn’t understand offensive and defensive efficiency?
Karl stated in the interview that Denver is beginning the process of preparing for next season. That process involves an evaluation of where this team is at, and what needs to be done to make it better. If you start such a process, though, with a distorted view of what is “good” and “bad”, it seems unlikely that you are going to end the process with an improved product.
Introducing the Distortion Score
To be fair to both Patrick and Karl, NBA observers do commonly refer to points score and allowed, rather than offensive and defensive efficiency. And as has been noted in many places (including The Wages of Wins), this common practice does distort our view of a team.
How much of a distortion do the common metrics create? To answer this question, I ranked each NBA team according to the following metrics:
- Points Allowed
- Points Scored
- Defensive Efficiency
- Offensive Efficiency
I then calculated the difference (labeled Defensive Difference) between the team’s defensive efficiency rank and its points allowed rank. Likewise, I also calculated the difference (labeled Offensive Difference) between the team’s offensive efficiency and points scored ranking. With these differences in hand, I calculated the team’s Distortion Score. This is determined as follows: (more…)
