NBA Defensive Rating: How Does It Work?

In the NBA, and most sports, it is said that defense wins championships. But measuring defensive ability can be difficult. Fortunately, there are some advanced metrics that can give NBA fans and NBA bettors a better look into what each team brings to the table on defense. One such metric is defensive rating, which can be used to determine which players and teams play the best on that side of the floor.

The short version of what NBA defensive rating is is that it helps to explain which teams or players in the NBA are the best at playing defense. There are key differences between the team and individual versions of this metric, which we will get to later in this guide to defensive rating. But the main thing bettors should know is that defensive rating can give you a better picture about the quality of defenses in the NBA.

The defensive rating NBA stat works slightly differently for individual players and their teams. The team version of this metric is the easiest to understand, so that is a good place to start. Defensive rating for teams is calculated by dividing the number of points scored by opponents by the number of possessions they had. That amount is then multiplied by 100, with a lower number meaning a better defensive rating.

For individual players, that same formula applies, though a key adjustment is made. Whereas team defensive rating measures those numbers for all defensive possessions that a team has, the individual metric accounts for possessions where a player is on the floor. There are more complex versions of this metric for individual players that detail possessions where players were directly responsible for stopping the opposing team. But the basic interpretation of defensive rating usually gives a good idea of who the best defenders are over a big enough sample size.

The top NBA player defensive rating in the NBA last season belonged to Giannis Antetokounmpo. In fact, several of the top defensive ratings for individuals this past season belonged to members of the Milwaukee Bucks. With the Bucks playing as well as they did on defense over the course of the season, it is no surprise that the Bucks had so many players at the top of the list.

Outside of members of the Bucks, Alex Caruso of the Lakers and Joel Embiid were at the top of the defensive rating charts for individuals. Again, this is largely a product of those players being on teams that boasted some of the best defenses in the league as a whole. But their individual contributions to those defenses made Caruso and Embiid undeniably deserving of their respective positions.

As far as NBA team defensive rating is concerned, there was no team that was better than the Milwaukee Bucks. Their 102.5 defensive rating suggests that they allowed 1.025 points per possession during the 2019-2020 season, the most impressive number in the league. Behind the Bucks were the Toronto Raptors with a defensive rating of 104.7 and the Los Angeles Lakers who finished the season with a defensive rating of 106.1.

Perhaps unsurprisingly, all three of those teams that led the league in defensive rating were in the top five in the NBA in net rating. Net rating is a team’s offensive rating minus their defensive rating. This gives context into how much more productive a team is on offense than it is on defense. With defense being so much more difficult than offense in the NBA, it stands to reason that the best defensive teams would have a huge edge in that regard.

In the postseason, the top defensive rating was earned by the Toronto Raptors with a defensive rating of 104.9. The Boston Celtics and Houston Rockets were behind the Raptors as the only two teams outside of Toronto to finish the postseason with a defensive rating under 107. In the playoffs, defense is so much more difficult, as teams are playing the best of the best scorers in the sport.

The most important thing to remember about defensive rating in NBA betting is that no statistic is perfect. In the case of defensive rating, the imperfection comes from the fact that there are possessions at the end of games where bench players are involved that can skew a defensive rating slightly. These possessions shouldn’t be enough to make a good defense look bad, or vice versa, but they can have subtle impacts on a team’s standing in that ranking.

It is also worth remembering that matchups can have an impact on defensive rating. A team that struggles to guard the perimeter could have their defensive rating negatively impacted after a game against a team that does its damage from the outside. The same can be said about teams that have trouble dealing with defending the paint when they are tasked with defending a team with scoring big men.

It is also worth remembering that NBA defensive rating is one of many statistics that bettors should think about when they place bets. Offensive rating and countless other metrics should be considered to determine whether teams have an advantage in a number of important areas on the court, or if that advantage only exists on defense.