The most common cliche of NBA basketball is that “defense wins championships”. In particular there’s a notion that fast paced, high-octane offenses don’t really win titles.
The Steve Nash-Mike D’Antoni Suns are pointed to as the extreme example of this. The “7 seconds or less” offense never managed to produce a title, despite the Suns having one of the best records over a span of multiple season in the 2000′s.
Interestingly enough, it’s actually true that offense doesn’t help you win titles. Below the graph shows the impact of offensive rating compared to expected playoff wins, and in particular how much a team is able to beat those wins (I calculated a regression model for the expected wins based on the last eight playoffs).
The correlation is actually negative, meaning that if you have a top-five offense, surprisingly you will win one fewer games in the playoffs. The discrepancy between offense and defense is so large in fact that if you are a top-five offense with a defense relative close to league average, compared to the opposite, you will lose an average of 3.2 wins per playoff run.
That may not sound like much, but it’s actually almost the difference of going one round further in the playoffs.
A great defense has two effects, it can either helps a lot or actually hurts you, as shown by the upside down “U” shape on the graph above. Generally though having a great defense is much more important than a great offense. If you are in the top-five in offense in a particular year, you are expected to win an additional game.
The fact that some great defensive teams have performed below expectations shows that you actually a functioning offense to win.
Ideally of course you’d have a solid offense and defense, but the point here is that the preference should building a defense first, while at least being mediocre on the other end.
So a great offense costs you a win, and the opposite on defense gains you a win in your expected win totals. Remember, in the playoffs it doesn’t matter how many you lose, as long as you can get to four in seven before the other team does.
The last chart shows the impact of assists on expected wins, which is a +1.5 games if you are in the top seven in assists in a give year. That’s surprisingly actually more important than defense.Ball movement is even more important than offense or defense when thinking about beating your playoff expected playoff win total. The Spurs are a perfect example of the type of problems you can create with ball movement and additionally making the right plays on offense and sticking to your system probably helps you on the defensive end.
As players are happier when they get to touch the ball on offense and will show more effort on defense.
The fact that assists are so important also shows something about teams being able to execute great sets to get easy scores, especially in crunch time.
Defense beats offense, but great teamwork is even more important than that.
*Stats per Basketball-Reference.com