The New Stats, Part Deux

Kurt —  December 29, 2004

With no Laker games until Sunday, this is a good time for some reflection and breakdowns of the team and its coaching thus far. But to do that properly, I believe I should lay down a little more foundation of the new statistical thinking in the NBA (call it “basketball money ball” or “NBA sabermetrics” or whatever you like).

The first piece I did on this was basically a glossary of terms, this time I will focus more on basic theory and application. While some of this may seem simplistic at first (the concepts are simple), we are building toward something. (It should be noted that what I’m talking about here is based on the work of other people, such as Dean Oliver, and places you can find more information are listed at the end of the article and in the links to the left.)

Let’s start with the most basic of questions: What wins basketball games? Obviously, scoring more points than your opponents — it’s been that way since the day James Naismith nailed up the peach baskets. However, by the basic rules of basketball, you and your opponents will have the same number of possessions per game, so what really is the key is being more efficient in your possessions than your opponent. (This concept is mentioned near the end of the first stats article I did.)

The best way to compare offenses and defenses is on a level playing field, usually 100 possessions (which is slightly more than in the average NBA game). For example, so far this season, for each 100 possessions the Lakers are averaging 105.4 points, sixth best in the league. However, they are giving up 102.9 points per 100 possessions to their opponents, an unimpressive 20th in the league.

Points per possession is a better barometer of a team than points scored per game because the latter is influenced by the pace games are played at (pace can be measured seperately). The Lakers are offensively efficient with their possessions, but because they average just 93.3 possessions per game (19th in the league, so much for the return to “Showtime”) they are averaging 98.4 ppg. (10th in the league).

If you take the difference between what a team scores per 100 possessions and allows per 100 possessions you come up with a spread that gives you a pretty good picture of who is playing the best ball in the league. Right now, the top five (according to Stats Pimp and that site’s in-house calculations) are San Antonio, Phoenix, Seattle, Dallas and Miami.

The next logical question is what factors lead to scoring on a possession? And, its corollary question, what can be done to stop an opponent from scoring?

Dean Oliver, in his groundbreaking book Basketball on Paper, says there are really only four ways to create offense on the team level: shoot accurately, don’t turn the ball over, grab offensive rebounds, and get to the free throw line. These things are not equal — shooting efficiency is twice as important and limiting turnovers and getting offensive rebounds. Getting to the free throw line is the least important.

That said, the teams that do these things well are successful. The five most efficient shooting teams (using eFG%, of course) this season are Phoenix, Miami, Seattle, San Antonio and Minnesota — the cream of the NBA crop.

How well you defend those four areas gives a good picture of a team’s defense. The five teams playing the best shooting defense (limiting opponents eFG%) are San Antonio, Houston, Chicago, Miami and Dallas. (I know seeing Chicago on the list is odd, but the Bulls play great defense, allowing opponents to score just 98.2 points per 100 possessions. The problem is they score only 94.6.)

Breakdowns of the four areas highlight the strengths and weaknesses of your team play at both ends of the floor.

There’s a lot more information on basketball statistics out there — things like value over replacement and efforts to predict how much better (or worse) an individual player will be in the coming year. Check out places like 82games, Stats Pimp or Knickerblogger on the Web, or buy the Basketball Forecast book put out by John Hollinger (it used to be called Basketball Prospectus, and it is the equivalent to Baseball Prosepectus) to find out more.

Update: The Soncis and Dean Oliver got an interesting write-up in the mainstream press this week. (Thanks to Knickerblogger for posting this.)


Kurt

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