Does Defense Really Win Championships?

In the latest Stat Stories episode, Chad Shanks and Justin Kubatko put an old cliché on trial to determine whether or not data supports the idea that defense wins championships in the NBA.

Listen to the embedded audio and browse through the StatMuse stats mentioned in the episode (data accurate as of the date of publication).

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After the Cavaliers fell to the Rockets on March 12, many were questioning their ability to repeat as champions given their poor defensive performance in the 2016–17 season.

Cleveland was able to grab the title last season despite just barely ranking in the top 10 for defensive rating (an estimate of the number of points a team allows per 100 defensive possessions).

Which team had the best defensive rating in 2015–16?

However, for this season they’ve fallen into the bottom 10 in defensive rating.

Which team has the worst defensive rating in 2016–17?

They’ve been worse in the second half, notching the second-worst defensive rating since the All-Star break.

Which team has the worst defensive rating this season since the All-Star Game?

Even though the Cavaliers still sit atop the Eastern Conference despite their defensive struggles, the two best records in the league at the moment happen to belong to the two teams with the best overall defensive ratings.

Which team has the best defensive rating in 2016–17?

The Spurs leading the league in defensive rating is nothing new. In fact, the’ve had the best defensive rating in the NBA over the last two decades.

Which team has the best defensive rating since 1996–97?

For those who believe there’s truth in the “defense wins championships” adage, it’s not just a coincidence then that the Spurs also happen to have the best winning percentage and are tied for the most championships in that span.

Which team has the best winning percentage since 1996–97?

However, when it comes to the playoffs, teams that have had the number-one defense have a cumulative record of 279–204 (.578) with six championships since the three-point line was introduced in the 1979–80 season. On the other hand, teams that have had the number-one offense in that same span have a cumulative playoff record of 311–204 (.604) and also six championships. This seems to indicate that teams are just as likely to win a championship with the number-one offense as they are with a number-one defense.

Only one team has won a championship since 1979–80 with both the number-one offense and the number-one defense — the 1995–96 Chicago Bulls.

Which team had the best offensive rating in 1995–96?
Which team had the best defensive rating in 1995–96?

Despite Michael Jordan himself insisting that “defense wins championships,” his title-winning teams actually ranked higher on offense more often than they did on defense.

Bulls ranks in title years:Offense: 1st, 1st, 2nd, 1st, 1st, 9th
Defense: 7th, 4th, 7th, 1st, 4th, 3rd

Overall, the average offensive rank by a champion in the three-point era is 5.4 while the average defensive rank is 5.2, indicating that title-winning teams don’t tend to skew to one side of the ball more than the other.

Even teams that have been more dominant on one side in a given season were always middle-of-the-pack at worst on the other side. In the three-point era, 31 playoff teams have finished in the top five in offense but in the middle in defense, accumulating a playoff record of 158–159 (.498) and two championships. On the other end, 35 playoff teams have finished in the top five in offense but in the middle in defense. They have a cumulative playoff record of 181–188 (.491) and one championship.

So, given the data available, it is technically accurate to say that defense does win championships, but so does offense. Championship-winning teams since 1979–80 were just as likely to be dominant on offense as they were on defense, but “Offense and defense wins championships!” isn’t as inspirational or as catchy a saying, so it’s not likely to catch on.

Sources/Further Reading:

Does Defense Really Win Championships in the NBA?
Surely you've heard the phrase during some portion of your life as a sports fan. Defense wins championships. It's an…

Defense Wins Championships, But It Won’t Win The MVP
Since 1994 when Hakeem Olajuwon last won the award, the MVP has moved away from

Scorecasting: The Hidden Influences Behind How Sports Are Played and Games Are Won
In Scorecasting, University of Chicago behavioral economist Tobias Moskowitz teams up with veteran Sports Illustrated…

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