NBA Offensive Rating Explained: Points Per 100 Possessions
Offensive Rating (ORtg) measures how many points a team scores per 100 possessions. It's the standard way to evaluate offensive efficiency in basketball because it strips out pace — a team that plays fast will score more raw points but isn't necessarily a better offense. Offensive Rating tells you how well a team converts each opportunity into points.
Why Not Just Use Points Per Game?
Because points per game conflates two things: how efficiently you score and how many chances you get. Consider two teams:
| Team | Points/Game | Pace | Off. Rating |
|---|---|---|---|
| Team A | 118 | 105 poss/game | 112.4 |
| Team B | 112 | 95 poss/game | 117.9 |
Team A scores more points per game, but Team B is the better offense. Team B converts possessions into points more efficiently — they just get fewer possessions because they play at a slower pace. If you ranked offenses by raw points, you'd conclude Team A is better. Offensive Rating tells you the truth: Team B is elite.
How Offensive Rating is Calculated
Team Offensive Rating = (Points Scored / Possessions) × 100 Where Possessions ≈ FGA - OREB + TOV + (0.44 × FTA) FGA = Field Goal Attempts OREB = Offensive Rebounds (these create new shot attempts, not new possessions) TOV = Turnovers FTA = Free Throw Attempts (0.44 accounts for and-ones, technical FTs, etc.)
The possession estimate isn't exact — it's an approximation because the NBA doesn't officially track possessions in the box score (though play-by-play data allows exact counts). The 0.44 multiplier for free throws is an empirically derived constant that accounts for the fact that not all free throws end a possession (and-one free throws, technical foul shots, three-shot fouls).
In the 2024-25 NBA season, offensive ratings typically range from about 108 (below average) to 120+ (elite). The league average hovers around 113-115. For context, any team consistently above 118 is historically excellent.
Why Per-Possession Metrics Matter
The per-possession philosophy extends beyond offensive rating. Defensive Rating (points allowed per 100 possessions) and Net Rating (offensive rating minus defensive rating) follow the same logic.
This matters most when comparing across eras or play styles:
- Era comparisons. The 2024 NBA plays at a much faster pace than the 2004 NBA. Raw point totals are incomparable. Per-possession stats let you compare across decades fairly.
- Matchup analysis. When a fast team plays a slow team, the game will have fewer possessions than two fast teams playing each other. Offensive Rating remains comparable regardless.
- Prediction. If you want to predict the score of a game, you need two things: how efficiently each team scores (offensive/defensive rating) and how many possessions the game will have (pace). Predictium's model separates these components explicitly.
The Prediction Connection
Predictium's B4 model uses offensive and defensive rating as core features, computed as EWMA with multiple half-lives (h10, h20, h40). This lets the model capture both a team's recent offensive form and their stable baseline efficiency — crucial for predicting how many points they'll score in tonight's game.
Team vs. Individual Offensive Rating
Offensive Rating exists at both the team and individual level, but they measure different things:
- Team ORtg is straightforward: team points ÷ team possessions × 100. It tells you how good the offense is overall.
- Individual ORtg estimates how many points per 100 possessions a player produces, including assists and other contributions. Dean Oliver's formula is complex and has known limitations — it can overrate high-usage players.
For individual player evaluation, RAPM is generally preferred over individual offensive rating because it isolates a player's impact from their teammates' contributions.
See real-time offensive ratings and team analytics for every NBA team.