What Is Defensive Rating in Basketball?

Defensive rating, often abbreviated as DRtg or DRTG, is one of the most important advanced statistics in basketball analytics. At its core, defensive rating measures the number of points an opponent scores per 100 possessions, providing a pace-adjusted view of how effectively a team prevents scoring. Unlike simply looking at points allowed per game, defensive rating accounts for the speed of play, making it possible to fairly compare defenses across different eras and teams with different playing styles.

The metric was pioneered by Dean Oliver, a legendary figure in basketball analytics, and introduced to the mainstream through his groundbreaking 2004 book Basketball on Paper. Since then, it has become the gold standard for evaluating defensive performance in the NBA, college basketball, and beyond.

Team vs. Individual Defensive Rating

It's crucial to understand that defensive rating can be calculated for both teams and individual players, and they serve different purposes.

Team defensive rating represents the collective effort of all five players on the court and is straightforward: how many points does the entire team allow per 100 possessions? This is the most reliable defensive metric because it captures the full picture of how a team's defense functions as a unit.

Individual defensive rating measures how many points an opponent scores per 100 possessions when a specific player is on the court. This is more complex and controversial. An individual player's defensive rating is heavily influenced by the other four players on the court, the defensive system employed by the coaching staff, and the overall quality of the team's defense. A great defender on a poor defensive team might have a worse individual defensive rating than an average defender on an elite defensive team, simply because of context.

This distinction is critical when analyzing player performance. While team defensive rating is a reliable metric for evaluating overall defensive strength, individual defensive rating requires careful interpretation and context.

How Is Defensive Rating Calculated?

The Basic Formula

The formula for defensive rating is deceptively simple on the surface but requires understanding several components:

Defensive Rating = (Opponent Points / Possessions) × 100

This formula tells us: for every 100 possessions the opponent has, how many points do they score? The lower the number, the better the defense.

However, calculating "possessions" is where the formula becomes more complex. Possessions are not simply the number of times a team has the ball. Instead, they account for field goal attempts, free throws, offensive rebounds, and turnovers:

The full possession formula is:

Possessions = 0.5 × ((Team FGA + 0.4 × Team FTA - 1.07 × Team OREB + Team TOV) + (Opponent FGA + 0.4 × Opponent FTA - 1.07 × Opponent OREB + Opponent TOV))

Once you have possessions and opponent points, the defensive rating calculation is straightforward: divide opponent points by possessions, then multiply by 100.

Understanding Possessions in the Formula

Why are possessions so important? Because basketball teams play at different paces. A team that plays fast, taking many shots per game, will naturally allow more total points than a slow-paced team—not necessarily because their defense is worse, but because they're giving up more possessions.

Consider two scenarios:

• Team A allows 110 points in a game where both teams take 100 total possessions (50 each). Their defensive rating: (110 / 50) × 100 = 220 DRTG (terrible).
• Team B allows 115 points in a game where both teams take 120 total possessions (60 each). Their defensive rating: (115 / 60) × 100 = 191.7 DRTG (still terrible, but relatively better).

Without the pace adjustment, you might think Team A had a worse game defensively. But when you account for possessions, Team B actually gave up a higher percentage of their opponent's possessions as points. This is why defensive rating is superior to raw points allowed for comparing defenses.

The Role of Defensive Stops

A defensive stop is any possession that ends without the opponent scoring. This can happen in several ways:

1. Forced missed shot — The defense pressures the offense into a poor shot that the defense rebounds
2. Turnover — The defense forces a turnover (steal or offensive foul)
3. Defensive rebound — The offense misses and the defense secures the rebound
4. Missed free throws — The defense fouls, the opponent misses both free throws, and the defense rebounds

Each of these outcomes contributes to a lower defensive rating. The more stops a team forces, the fewer possessions the opponent has and the fewer points they'll score per 100 possessions.

What Is Considered a Good Defensive Rating?

Benchmarks Across NBA History

Understanding what constitutes a "good" defensive rating requires knowing the historical benchmarks and how they've evolved.

Important note: These benchmarks have shifted over time. In the 1990s and 2000s, a defensive rating below 95 was considered elite. Today, due to the increased pace of play and the 3-point revolution, a defensive rating between 100-105 is considered elite in the modern NBA.

How Modern NBA Pace Affects Ratings

The NBA has undergone dramatic changes in the last 15-20 years that have directly impacted defensive rating benchmarks:

1. The 3-Point Revolution — Teams now take far more three-pointers than ever before. Three-point attempts have nearly doubled since the early 2000s. More three-point attempts means more possessions and more opportunities for opponents to score.

2. Increased Pace of Play — Teams play faster, transition more frequently, and push tempo more aggressively than in the isolation-heavy 1990s and early 2000s. This means more possessions per game overall.

3. Spacing and Spacing Efficiency — Modern players are better shooters, and teams space the floor more effectively. This makes it harder for defenses to camp in the paint, leading to more efficient opponent scoring.

Because of these factors, league-wide defensive rating has increased. What was a 105 DRTG in 2005 (good-to-very-good) might be a 110 DRTG today (average). The elite teams of the 2020s typically have defensive ratings in the 100-105 range, whereas elite teams from the 1990s often had ratings in the 90-95 range.

Top Defensive Ratings in NBA History

Since defensive rating began being tracked in the 1999-2000 season, several players have achieved historically elite individual defensive ratings:

Ben Wallace's 87.48 DRTG in 2003-04 remains the lowest (best) individual defensive rating ever recorded. This was achieved during the peak of the Detroit Pistons' defensive dominance, when the team was built around elite interior defense and a suffocating defensive system. Wallace's combination of shot-blocking, rebounding, and defensive positioning created an almost impenetrable interior.

How Does Defensive Rating Differ From Offensive Rating?

Comparing the Two Metrics

Offensive rating and defensive rating are mirror statistics. Where offensive rating measures how many points a team scores per 100 possessions, defensive rating measures how many points they allow per 100 possessions.

Offensive Rating = (Points Scored / Possessions) × 100 Defensive Rating = (Points Allowed / Possessions) × 100

Both metrics use the same possession calculation and both are pace-adjusted. This makes them directly comparable and complementary.

The key insight is that a team's offensive rating is the opponent's defensive rating, and vice versa. If Team A has an offensive rating of 110 and plays against Team B, then Team B's defensive rating against Team A is 110. This symmetry is one of the elegances of these metrics.

Net Rating: The Combined Picture

When you subtract a team's defensive rating from their offensive rating, you get net rating, one of the most predictive metrics in basketball:

Net Rating = Offensive Rating - Defensive Rating

Net rating tells you the point differential a team would have in a game against an average NBA team. A team with an offensive rating of 115 and a defensive rating of 105 would have a net rating of +10, meaning they'd be expected to beat an average team by 10 points.

Net rating is remarkably predictive of championship success. Historical analysis shows that championship teams almost always have positive net ratings, and the larger the net rating, the more dominant the team. The best championship teams typically have net ratings of +8 to +15 points.

This data reveals an important truth: to win a championship, you don't necessarily have to be the best at both offense and defense. However, you must be elite at one and at least very good at the other. The San Antonio Spurs, for example, won five championships over 16 years by consistently prioritizing elite defense (never worse than 3rd in the league) while maintaining good-to-excellent offense (ranging from 5th to 11th).

Why Defensive Rating Matters for Betting

Using Defensive Rating in Over/Under Markets

Defensive rating is one of the most powerful tools for predicting over/under outcomes in basketball betting. Here's why:

Teams with poor defensive ratings (above 110-115) allow significantly more points than average. When you see a matchup where one team has a strong offensive rating and the other has a poor defensive rating, the total points are likely to be high. Conversely, when both teams have strong defensive ratings, totals tend to be lower.

Practical Example:

• Team A: Offensive Rating 115, Defensive Rating 108 (strong offense, average-to-good defense)
• Team B: Offensive Rating 105, Defensive Rating 115 (average offense, poor defense)

In a matchup between these teams, the total is likely to be inflated. Team A will likely score well against Team B's weak defense, and while Team B might struggle offensively against Team A's decent defense, they'll still find buckets. The over is more likely in this scenario.

Identifying Vulnerable Defenses

A defensive rating above 115 is a red flag. It indicates a team is genuinely vulnerable defensively and will likely struggle against better offenses. When a team with a 115+ DRTG faces an opponent with an above-average offense, the under is unlikely to hit—the game will likely be high-scoring.

Conversely, when two teams with strong defensive ratings (both under 105) play each other, the total is often set higher than the actual likely outcome, creating value on the under.

Key defensive rating thresholds for betting:

• Under 100: Elite defense, strong under candidate
• 100-105: Very good defense, slight under lean
• 105-110: Average defense, neutral
• 110-115: Weak defense, over lean
• Above 115: Poor defense, strong over candidate

Defensive Rating Trends and Momentum

Season-long defensive rating tells an important story, but recent trends matter even more for betting purposes. A team's defensive rating over the last 5-10 games is more predictive of their near-term performance than their season average.

Why? Because:

1. Injuries — A team might have a poor season-long DRTG because they lost a key defender to injury. If that player recently returned, their defense has likely improved significantly.

2. Lineup Changes — Trades, call-ups, or adjustments to the rotation can dramatically shift defensive performance.

3. Momentum — Teams go through defensive stretches. A team that has allowed 100 points per 100 possessions over the last 5 games is playing better defense than their season average of 108.

4. Opponent Adjustments — Coaches make adjustments. A team that was struggling defensively might have simplified their scheme or adjusted their personnel groupings.

Smart bettors always check both season-long and recent defensive rating trends before making over/under decisions.

Common Misconceptions About Defensive Rating

Misconception 1: "Low Points Allowed = Great Defense"

One of the most common mistakes casual fans make is looking at raw points allowed per game without considering pace. A team that allows 100 points per game but plays at a slow pace might have a worse defensive rating than a team that allows 110 points but plays at a fast pace.

Defensive rating corrects for this by dividing by possessions. It's the pace-adjusted version of points allowed, making it the proper metric for comparing defenses across different teams and eras.

Misconception 2: "Individual Defensive Rating Tells the Whole Story"

An individual player's defensive rating is heavily dependent on their teammates. A great defender on a poor defensive team might have a 105+ DRTG, while an average defender on an elite defensive team might have a 95 DRTG. This doesn't mean the average defender is better—it means the system and teammates matter enormously.

This is why context is critical when evaluating individual defensive ratings. A player's DRTG should always be considered alongside:

• Their team's overall defensive rating
• Their position and defensive role
• The quality of their teammates
• The defensive system employed

Misconception 3: "Defense Doesn't Win Championships"

Some fans believe that in the modern, offense-heavy NBA, defense is secondary. Historical data contradicts this. Analysis of championship teams from 1980 to 2024 shows that elite defense is a common thread among champions. While teams don't need to be #1 in defensive rating to win, they consistently need to be in the top 5-10.

The 2004 Detroit Pistons, for example, had the 18th-ranked offensive rating in the league but won the championship because of their elite defense (1st in DRTG). Conversely, the 2001 Los Angeles Lakers had the 2nd-ranked offense but only a 21st-ranked defense—they won because their offense was historically dominant, not despite their poor defense.

The lesson: you need elite performance on at least one side of the ball, and you can't be terrible on the other side. Defense remains a critical component of championship basketball.

The History and Evolution of Defensive Rating

Dean Oliver and the Birth of Advanced Defensive Metrics

Before Dean Oliver, evaluating defense in basketball was largely subjective. Scouts and analysts relied on watching games, counting steals and blocks, and making educated guesses about which players were good defenders. There was no objective, statistical way to compare defenses across teams and eras.

In the early 2000s, Dean Oliver revolutionized basketball analytics by introducing the concept of offensive and defensive rating. His methodology was published in the 2004 book Basketball on Paper: The Science of Basketball Explained, which became the bible for basketball analysts. Oliver's insight was that by dividing points by possessions, you could create a pace-adjusted metric that fairly compared defenses regardless of how fast or slow a team played.

Before Oliver's work, advanced basketball statistics were virtually non-existent in mainstream sports. His pioneering research laid the foundation for the entire field of modern basketball analytics, which has transformed how teams evaluate players, design strategies, and make personnel decisions.

How Defensive Rating Has Changed Over Time

The NBA has undergone significant evolution, and defensive rating benchmarks have shifted accordingly:

1990s Era (Peak of Hand-Check Defense):

• Elite defensive ratings: 90-95 DRTG
• Average: 105-108 DRTG
• Slower pace, more physical, isolation-heavy offense
• Teams like the Chicago Bulls and Miami Heat could suffocate opponents

2000s Era (Post-Hand-Check Rule Change):

• Elite defensive ratings: 95-100 DRTG
• Average: 105-110 DRTG
• Slightly increased pace, more spacing
• The San Antonio Spurs' dynasty thrived with elite defense

2010s Era (Rise of 3-Point Shooting):

• Elite defensive ratings: 100-105 DRTG
• Average: 108-112 DRTG
• Significantly increased pace, spacing, and three-point volume
• Defenses struggled to adapt to spacing and pace

2020s Era (Modern NBA):

• Elite defensive ratings: 100-105 DRTG (sometimes below 100)
• Average: 110-115 DRTG
• Very fast pace, extreme spacing, highest three-point volume
• Defensive rating inflation across the league

The trend is clear: league-wide defensive rating has increased over time due to rule changes, increased pace, and the 3-point revolution. What was elite 25 years ago would be above-average today.

Limitations and Context of Defensive Rating

Why Defensive Rating Isn't Perfect

While defensive rating is the best pace-adjusted defensive metric available, it has limitations:

1. Team Dependency — Individual defensive rating is heavily influenced by teammates. You can't isolate one player's defensive contribution perfectly.

2. System Dependency — A defensive system designed to allow open three-pointers to protect the paint might have a higher DRTG but still be effective. Conversely, a system that pressures every shot might have a lower DRTG but also force more turnovers.

3. Doesn't Capture All Defensive Actions — Defensive rating doesn't measure:

   • Pressure applied on the ball handler
   • Positioning and anticipation
   • Communication and effort
   • Screen defense and help rotations
   • Defensive intensity and focus

4. Doesn't Account for Opponent Quality — A team's defensive rating is affected by the quality of opponents they face. A team that plays weak offenses will have a better DRTG than a team that plays strong offenses, even if their actual defense is identical.

Other Defensive Metrics to Consider

To get a complete picture of defensive performance, use defensive rating alongside these metrics:

The best defensive analysis uses multiple metrics. A team might have a high defensive rating (poor) but a low opponent field goal percentage (good), suggesting they allow efficient scoring through free throws and transitions rather than poor perimeter defense.

Frequently Asked Questions

Q: What is a good defensive rating in the NBA? A: In the modern NBA (2020s), a defensive rating between 100-105 is considered elite. A rating between 105-110 is very good, and anything above 115 indicates a struggling defense. In the 1990s and 2000s, elite ratings were below 95, but the increased pace and three-point volume have inflated these benchmarks.

Q: How is defensive rating calculated? A: Defensive Rating = (Opponent Points / Possessions) × 100. Possessions are calculated using a formula that accounts for field goal attempts, free throws, offensive rebounds, and turnovers. The formula is: 0.5 × ((FGA + 0.4 × FTA - 1.07 × OREB + TOV) + (Opponent FGA + 0.4 × Opponent FTA - 1.07 × Opponent OREB + Opponent TOV)).

Q: What is the difference between team and individual defensive rating? A: Team defensive rating measures how many points the entire team allows per 100 possessions and is a reliable metric. Individual defensive rating measures how many points opponents score per 100 possessions when a specific player is on the court, but it's heavily influenced by teammates and system, making it less reliable for player evaluation.

Q: Why is defensive rating better than just looking at points allowed? A: Defensive rating is pace-adjusted. Two teams might allow 105 and 110 points per game respectively, but if one plays fast and one plays slow, their actual defensive efficiency could be reversed. Defensive rating accounts for possessions, making it a fair comparison.

Q: Does defensive rating matter for betting? A: Yes, significantly. Teams with poor defensive ratings (above 115) allow more points and make over bets more likely. Conversely, teams with elite defensive ratings (below 105) make under bets more attractive. Recent defensive rating trends (last 5-10 games) are especially predictive.

Q: Who has the best defensive rating in NBA history? A: Ben Wallace holds the record with a 87.48 individual defensive rating in the 2003-04 season with the Detroit Pistons. Historically, defensive ratings have become higher (worse) over time due to increased pace and three-point volume, so comparing across eras requires context.

Q: How does defensive rating relate to winning? A: Championship teams almost always have either an elite offensive or elite defensive rating (or both). Net rating (offensive rating minus defensive rating) is highly predictive of championship success. The San Antonio Spurs won five championships by consistently prioritizing elite defense.

Q: What is net rating? A: Net rating = Offensive Rating - Defensive Rating. It represents the point differential a team would have against an average NBA team. A +10 net rating means a team would be expected to win by 10 points against an average opponent. Net rating is one of the most predictive metrics for championship success.

Related Terms

• Offensive Rating — Points scored per 100 possessions, the offensive counterpart to defensive rating
• Net Rating — The difference between offensive and defensive rating, indicating overall team efficiency
• Pace Factor — The number of possessions per 48 minutes, crucial for understanding pace-adjusted metrics