Does defence really win championships?

As an NBA fan, when you hear the phrase "defence wins championships," who do you think of? 

There's the 'bad-boy' Detroit Pistons of the early 90s, with a nothing-easy approach to basket drives. Or is it the San Antonio Spurs later in the same decade, with the twin-tower combo of David Robinson and Tim Duncan? For many of you, it'll be the 03/04 Pistons, who took their defensive presence to another level to win one of the most storied NBA championships in history. 

However, is the old mantra true in the 2020s, where we see the highest scoring in history, and many fans denigrate the lack of defensive effort from their teams?

Last year's champion Denver Nuggets were joint 13th in the league in defensive rating at 114.2, and only had the league's fifth-best offensive rating as well. In this position, it looks like they came with an outside shot of winning it all, but critics and analysts alike agreed that they put together one of the most formidable starting lineups in the league, and the bookies had them with the fifth best odds to win it all at the start of the playoffs in 2023.

Another puzzling example is Stephen Curry's Warriors. A dynamic player like Steph is most definitely primarily associated with offence, those half-court buzzer beaters that seem to spring from his hands like it's nothing. However, his Warriors teams have twice managed to win championships behind a #1 defence, and whilst in 2015 they also had the #2 offence, their historic 2022 championship saw them winning with the #17 defence in the league somehow.

If we accept the rule that defence is necessary to win it all, then I'm a happy man, as my Timberwolves sit at #1 in defensive rating this season off the work of 2-time DPOY Rudy Gobert and Jaden 'Seatbelt' McDaniels. However, nobody, not even my most optimistic essence, thinks that the Wolves are on their way to winning it all. So why does it appear not only that defence is so important, but that it's increasingly rare in this decade of the NBA?

Well, statistically, the importance of defence for winning a championship is similarly weighted compared to offence. In history, the winners of the championship have been around the 3.1th mark in offence and the 3.2th mark in defence. So outwardly there is no difference, but are we flattening the curve too much by taking such a large range of time?

Analysing decades individually, we see that the last 10 years not only represent an increase in unpredictability from season performance to championship result — perhaps due to the increase in load management and stars sitting out the regular season to wait for the playoffs —

but also we see the first 10-year period where defensive ranking becomes lower on average for champions than offensive ranking:

2014 - 2023: 5.9 OFFRTG Avg, 6.0 DEFRTG Avg

2000 - 2009: 6.8 OFFRTG Avg, 5.3 DEFRTG Avg

1990 - 1999: 5.9 OFFRTG Avg, 4.3 DEFRTG Avg

Aside from the smaller results set being skewed more strongly by outliers like the #18 Offensive ranked 2004 Pistons, or the 1995 Rockets who were outside of the top 6 in both categories, we see that the necessity of being the league's best defence has faded in recent years somewhat.

So, are the Timberwolves going to miraculously win the NBA championship this year with the league's best defence. If we've learned anything from this investigation, god only knows.

Image: Wikimedia Commons