What is Defensive Rating? Basketball stat explainer

Defensive Rating (DRtg) is one of the most popular statistics to evaluate how good a team or player is on defense, and it's become much more popular in recent years.

Fans may wonder how it is calculated and why it is sometimes used instead of the less confusing, more common statistic of points allowed per game. We discuss all of that and more in this article.

What is Defensive Rating?

Defensive Rating is a basketball statistic that normalizes a team's or player's points allowed to 100 possessions.

In addition to turnovers forced and shots blocked, DRtg also accounts for stops, which is hard to define but includes forced missed shots and team turnovers forced, among other factors.

Essentially, the stat answers the question of how many points a player gives up over 100 possessions when an opponent tries to score on that player. The lower a team or player's DRtg is, the better that team or player is on defense.

Why is Defensive Rating important?

Evaluating a team's points allowed based on possessions rather than on a per-game basis allows analysts and fans to evaluate a team's ability to limit opponents' scoring without accounting for the influence of a game's pace.

Teams can have any number of possessions in a given game, so normalizing to 100 possessions allows people to view a number of points within an identical sample size of scoring chances.

For example, the team that played at the fastest pace in the 2021/22 NBA season – the Minnesota Timberwolves with 100.9 possessions per game – also ranked in the bottom seven teams in points allowed per game (113.3). Because their games had the most possessions, their opponents had more opportunities to shoot, leading to more points scored.

But, when looking at the 2021/22 T-Wolves' Defensive Rating, it ranked at a pretty decent 13th in the NBA at 111.7 points allowed per 100 possessions.

In that same season, the team with the best DRtg – the Golden State Warriors at 106.9 – ranked 13th in pace (98.4 possessions per game), but their middling pace and stellar ability to limit opponents' efficiency saw them allow the third-fewest points per game that season (105.5).

Slower-paced teams usually allow fewer shots per game which leads to fewer points allowed per game, and vice-versa for faster-paced teams.

How does team Defensive Rating work?

Team DRtg takes a team's points allowed per game average with the team's pace, and scales the team's points allowed per game average to 100 possessions.

Team DRtg is more popular than the individual version because it's a more uniform version of points allowed per game. Defensive Rating illustrates a team's ability to limit its opponents' offensive efficiency.

How does individual player Defensive Rating work?

A lot of math is involved to find a single player's Defensive Rating, but essentially, a player's number of points allowed is divided by that player's individual total possessions on the court where opponents try to score on him. Then, the number from that equation is then multiplied by 100.

Points allowed accounts for the number of points a player concedes by being scored on or by allowing an assist. Calculating individual possessions is the longest and most difficult part of the equation, but, put simply, it accounts for any possession where the player in question guards an opponent who scores, shoots, provides an assist or commits a turnover.

The individual version of DRtg is often impacted by how active a player is within his team's defensive structure, meaning a player with more steals and blocks will have a better DRtg than another defender who prioritizes positioning rather than forcing turnovers because steals and blocks are the preeminent counting stats on defense.

That's why an elite perimeter defender like Bruce Bowen – who earned eight career All-Defensive honors but only averaged over 1.0 steal in five of his 13 NBA seasons – has a worse career defensive rating (102 DRtg) than a prolific shot blocker like Ben Wallace (96 DRtg).

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