Defensive Rating (often abbreviated as DRtg) is an advanced basketball metric that measures efficiency by tallying the number of points a team or player gives up per 100 possessions. It removes the speed of the game from the equation to find out who actually stops the opposing offense most effectively. A low rating means a team or player allows fewer points, making them a better defensive unit.
Traditional basketball statistics focus on raw per-game totals. A fan looking at a box score might see a team giving up 115 points a night and assume their defense is terrible. Defensive Rating ignores the raw total and looks at the rate of scoring. It levels the playing field between teams that play at a breakneck speed and teams that grind the clock down to the final seconds.
Author and basketball statistician Dean Oliver first introduced the metric to the mainstream in his 2004 book, Basketball on Paper. Front offices and coaching staffs quickly adopted it. Today, it is a standard tool used by analysts to evaluate team efficiency across an 82-game regular season schedule.
How Defensive Rating Works
The math behind a team’s Defensive Rating is surprisingly straightforward. You take the total points allowed by a team, divide that number by the total number of possessions they defended, and multiply the result by 100. This standardizes the metric. It gives you a clean look at exactly how many points a team surrenders every 100 times the opposing offense gets the ball.
A possession ends when a team attempts a field goal, commits a turnover, or shoots the final free throw of a foul sequence. Rebounding the ball on offense extends a single possession. By counting these events, statisticians track the exact volume of opportunities a defense faces during a 48-minute basketball game.
Individual Defensive Rating is much harder to pin down. The formula for a single player relies heavily on quantifiable box score data to estimate the number of defensive stops they force per 100 possessions while they are on the court. A “stop” in this context includes steals, blocks, defensive rebounds, and forced turnovers.
The individual metric also factors in team defensive metrics and the league average. Because of this, an individual’s rating is heavily influenced by the four other players sharing the court with them. A player logging high minutes on an elite defensive team will naturally see a boost in their individual DRtg.
Why Teams Use This Metric
Pace is the defining variable in modern professional basketball. Some teams push the ball in transition after every missed shot. Other teams walk the ball up the court and run deliberate, 20-second half-court sets. This difference in pace completely warps traditional counting stats.
A team that plays incredibly fast will naturally use more possessions per game. This gives the opposing team more possessions as well. Even if that fast-paced team plays excellent defense on a per-possession basis, they will still surrender a high number of total points simply because the opponent had more chances to score. Traditional stats like points allowed per game punish teams that play fast, whereas DRtg standardizes the metric to 100 possessions to reveal true efficiency.
Coaches use Defensive Rating to evaluate specific five-man lineups. If a coach wants to know whether a specific group of bench players is holding their own defensively, they look at the group’s DRtg over a stretch of games. This tells the coaching staff if the unit is actually forcing missed shots or just getting lucky with a slow-paced game.
Famous Examples from Major Games
The 2012-2013 San Antonio Spurs are the textbook example of why pace adjustments matter. During that regular season, the Spurs ranked 11th in the league in traditional points allowed, giving up 96.6 points per game. To a casual observer, they looked like an average defensive team.
But the Spurs ran a fast-paced offense that naturally gave their opponents more possessions. When you adjusted for that speed, their actual defensive efficiency was elite. They ranked 3rd overall in Defensive Rating that year, giving up only 99.2 points per 100 possessions. The raw points-per-game stat lied about their defensive quality, but DRtg told the truth.
Looking further back, historical tracking data shows how pace dictated scoring in earlier eras. The 1973-1974 Milwaukee Bucks played at a grindingly slow pace of 107.9 possessions per game. Their raw scoring totals were artificially depressed by this slow pace. However, their offensive rating of 99.3 points scored per 100 possessions was actually the best in the league that year.
Common Misconceptions
The biggest criticism of Defensive Rating is its application to individual players. It is functionally impossible to isolate one player’s defensive impact from the other four players on the court using this formula alone. DRtg is an excellent tool for evaluating an entire team, but it is deeply flawed for comparing individual players across different rosters.
Boris Diaw’s career provides perfect evidence of this flaw. In the early 2010s, Diaw’s individual defensive rating consistently hovered around 110 while he played for struggling teams like the Atlanta Hawks, Phoenix Suns, and Charlotte Bobcats. He gave up about 110 points per 100 possessions. Then, he was traded to the defensively stout San Antonio Spurs.
His defensive rating miraculously dropped to 102 almost overnight. Diaw did not suddenly become a lockdown defender in his 30s. He simply started playing alongside better defenders in a better system. The metric gave him credit for the team’s overall success.
A similar shift happened to center Omer Asik. Between 2011 and 2013, Asik boasted a DRtg in the 99th percentile while playing for a rigid, defensive-minded Chicago Bulls team. He then signed with the Houston Rockets. The Rockets featured weaker perimeter defenders at the time. Opposing guards frequently blew past the initial point of attack, leaving Asik in impossible 2-on-1 situations at the rim. His DRtg plummeted to the 80th percentile, despite his individual rim-protection skills remaining exactly the same.
The metric also suffers from an intense box score bias. Individual DRtg relies heavily on quantifiable stats like steals and blocks. It inherently under-rewards elite positional defenders who contest shots, cut off passing lanes, or force players into bad shots without actually registering a blocked shot. An elite defender who completely denies their man the ball gets zero credit in the formula because no steal or block occurred.
The Shift Toward Matchup Tracking
Because traditional DRtg has well-documented limitations at the individual level, modern analytics departments are moving toward granular defensive matchup data. Rather than relying solely on team-based averages, teams now track how well a specific defender performs when guarding a specific opponent.
This is crucial for evaluating defensive versatility. Teams want to know a perimeter defender’s exact success rate when switched onto a larger forward, especially when trying to defend a modern offense that runs a point-center scheme with high-level passing. It answers the question of isolation defense far better than a per-100-possession average.
Advanced data sets now utilize tracking cameras in the arenas to generate new metrics. Statistics like Adjusted Plus-Minus (APM) and “DRIP” attempt to better isolate an individual’s defensive performance from the surrounding team noise. These models project a player’s true per-100 possession contribution regardless of who they share the floor with.
Frequently Asked Questions
Who invented the defensive rating metric in basketball?
Defensive Rating was created by author and basketball statistician Dean Oliver. He introduced the metric to the wider sports analytics community in his 2004 book, Basketball on Paper.
Why is Defensive Rating considered better than Points Allowed Per Game?
Defensive Rating adjusts for a team’s pace of play. A team that plays fast will have more possessions per game, which naturally gives the opposing team more chances to score. By standardizing the metric to points allowed per 100 possessions, Defensive Rating provides a pure measure of defensive efficiency, regardless of how fast or slow a game is played.
Is individual Defensive Rating a reliable way to measure a player’s defense?
No, analysts consider it highly controversial when used for individuals. Individual DRtg is heavily skewed by the defensive abilities of a player’s teammates. A poor defender on a great defensive team will often have a better individual DRtg than an elite defender playing on a terrible team.
What is the formula for calculating a team’s Defensive Rating?
The formula for a team’s DRtg is: (Points Allowed ÷ Total Possessions) × 100. This determines exactly how many points a defense gives up for every 100 possessions the opposing team uses.
Why does Defensive Rating ignore positional defense?
The individual formula relies on traditional box score stats like blocks, steals, and rebounds. If a player plays perfect positional defense and forces a bad shot without recording a block or a steal, the traditional formula has no mathematical way to reward them for that specific play.