Monday, March 16, 2009

Suns and Warriors Put On a Show (And Demonstrate Why Pace Matters)

Last night the Phoenix Suns and the Golden State Warriors, two of the fastest paced teams in the NBA, were matched up against each other on national television. Because of the entertaining nature of their respective styles of basketball (the return of "7 seconds or less" matched up against Nellie-ball), I'd been looking forward to this game all last week. And when it finally came, it didn't disappoint anyone who likes seeing a ball go through a hoop. Both teams put up what in baseball are known as "crooked numbers," and after the smoke cleared, the Suns prevailed, 154-130.

(No word yet on the state of the scoreboard. Technicians are working around the clock trying to revive it. It could last be heard muttering, "There will be no rematch.")

The Suns this year have rightfully been criticized for their lack of defense. While they rank second in the NBA (trailing only the Western-conference-leading LA Lakers) in offensive efficiency, their record is only 36-31, placing them 9th in the West, trailing the Dallas Mavericks by 4 games in the hunt for the last playoff spot. This is a product of their woeful defense, which ranks 23rd in the league in defensive efficiency.

Last night, matched up against a Golden State team that plays at the fastest pace in the league, the Suns defense lived up to their dismal billing, giving up an incredible 130 points. Thank God for their offense, which scored a season-high 154 points.

But was their defense as bad as the scoreboard makes it look?

Offensive and defensive performance is generally measured purely by points scored and points allowed. At least by non-geeks. But we geeks have been asking ourselves for some time whether or not this way of measuring performance actually captures what really happened on a basketball court. Not surprisingly, our answer has been a resounding "NO!" And that's why generally, rather than talk about points scored I talk about "efficiency."

Offensive and defensive efficiency is a way of measuring performance adjusted for pace. It is, in other words, the simple recognition that basketball played at a faster pace will, all other things being equal, include more points, and basketball played at a slower pace will, all other things being equal, include fewer points. This is because, the faster the game, the more possessions. The more each team has the ball, the more chances to score. The more chances to score, the more points on the board. Pretty simple.

The Detroit Pistons are an excellent example of this. They have long been rightly regarded as a good defensive team. This year, while it has been clear that their defense has slipped a little, is no exception. They are giving up only 94.2 points per game, very low for an NBA team. So there defense has been pretty good, right?

Not really. The Pistons play at the second slowest pace in the NBA. That means, in a Pistons game, each team has the ball less times than in an average NBA game. Which means in turn that each team has fewer chances to score. Fewer chances to score leads to less points on the board, which leads to the impression that they are still an elite defensive team.

But if you look at what happens in each of the possessions, it become clear that they aren't. Their defensive efficiency for the season is 104.5. That means that they surrender 104.5 points per every 100 possessions, or roughly 1.045 points each time the other team has the ball. That isn't awful, but it isn't great either, ranking 13th in the NBA. It is middle of the pack.

The LA Lakers, by contrast, are considered an elite offensive team that struggles at times on defense. They give up 100.4 points per game, a stat cited by TV talking heads to indicate that they really need to work on that end of the floor if they want to win the title this year. And, maybe they do. Since they have the top offense in the league, defense is clearly their weakness. Their relative weakness, anyway. Because of their fast pace (they are the fifth-fastest team in the league) they surrender over 6 points per game more than the Pistons. But efficiency indicates that they are actually a better defensive team than the Pistons, ranking 6th in the league, at 102.6. That means, over the course of 100 possessions, the Lakers give up 1.9 fewer points than the Pistons.

That brings us back to the Suns-Warriors game last night. The Suns put on an absolute show, scoring 154 points. It was an incredible display. In route to their 154 points they posted an offensive efficiency of 138.12. To put that in perspective, for the season their offensive efficiency is 2nd in the NBA, at 110.4. The Lakers lead the league at 110.8. An offensive efficiency of 138.12 is every bit as incredible as 154 points. It is a truly stunning number, almost 30 points per 100 possessions better than the best season-long mark in the league.

The glow from that was dimmed a bit by the fact that they surrendered 130 points. That's 23 more points that the most allowed by any team not in Oakland last night. But was it the second-worse defensive performance of the night?

Yes. But not by as much as you might think.

Last night the Dallas Mavericks also had a hard time on the defensive end. It was, in fact, almost exactly as bad as the Suns' performance, but the extreme difference in pace obscures that.

In surrendering 130 points to the Warriors last night, the Suns posted a dismal defensive efficiency of 116.07. That's almost 5 full points per 100 possessions worse that the Sacramento Kings' rock bottom 111.1. But in surrendering 107 points to the Lakers last night the Mavs posted an almost as bad 115.05. When adjusting for pace, a 23 point difference becomes a 2 point difference. That's one missed shot away from being a tie.

How can this be?

It's simple, really. The Lakers scored their 107 points on roughly 93 possessions. That means they had the ball about 93 times, and got 107 points out of it. The Warriors, who play at the fastest pace in the NBA and were matched up against another team that likes to get out and run, by contrast, had roughly 112 possessions in route to their 130 points. They had the ball a whopping 19 more times than the Lakers, and got 23 more points out of it.

That's the difference right there.

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