I have a confession: I hate the word efficiency in connection with basketball. It’s a fundamental concept, it quite literally is the whole game, and it’s a stupid damn term that doesn’t really describe what it means or why it’s important.

For that matter, offensive and defensive rating are also terrible names.

When most people hear “efficiency,” it usually calls to mind things like energy or outputs produced per inputs. Except for basketball degenerates, it doesn’t conjure thoughts of NBA players making/missing shots or committing turnovers.

“Rating” calls to mind subjectivity like rating a movie or a restaurant or a Lyft driver. But that’s not at all what offensive and defensive ratings are in basketball.

This isn’t just nitpicking. The names of things matter. Words like “efficiency” and “rating” sound nerdy and wonky. Which is okay, except that those of us who use these tools often have to explain what the hell they mean.

For teams, offensive efficiency (or offensive rating) is average points scored per 100 possessions. A possession begins when one team has the ball and ends when the other team gets it back. Possessions often include multiple events or actions, including offensive rebounds, assists, steals, blocks, turnovers, fouls, etc. They’re the basic currency of basketball — teams use offensive possessions to try to score. They spend defensive possessions trying to stop the other team from scoring.

Per something stats are a normal part of sports. In baseball, there’s ERA, which stands for Earned Run Average, which is earned runs allowed per nine innings pitched. In football, there’s yards per carry, yards per pass attempt, even completions per 100 attempts (umm, that’s called completion percentage).

The reason it’s better for analysis to per possession stats rather than per game (or even per minute) in basketball, is that teams play at different speeds, which means the number of possessions vary game to game. What’s important is what teams and players do with their possessions.

For individual players, what’s called offensive rating or offensive efficiency is points produced per possession used x 100. It includes the value of shooting the ball from the floor and free throw line, offensive rebounds, assists and turnovers.

The TLDR for the above is this: offensive efficiency in basketball is a measure of how often a team scores when it uses a possession. Defensive efficiency measures how often a team prevents a score when the other team uses a possession.

Because efficiency is what wins games, the best offensive players are the ones who can use possessions to produce points. The best defensive players are able to limit the ability of the opposing team to use their possessions to score.

About 450 words ago, you were probably wondering what any of this has to do with the Wizards and the Warriors matchup on Monday afternoon. And I promise there’s a point.

So let’s look at the offensive performances of Kyle Kuzma and Deni Avdija. For the game, Washington had an offensive rating of 116. (That’s 118 points divided by 102 possessions multiplied by 100 and rounded to the nearest whole number.)

Here’s Kuzma’s contribution — 5-20 from the floor, 4-12 from three-point range, 2-4 from the free throw line, 3 offensive rebounds, 5 assists and 6 turnovers. Altogether, he used 26 possessions to produce 18 points. He was on the floor for 85 possessions, which gives him a usage rate of a little over 30%.

Avdija was 3-9 from the floor, 0-2 from three, attempted no free throws, had 2 offensive rebounds, 2 assists and 2 turnovers. He used 10 possessions (a usage rate of about 34%) to produce 7 points. CORRECTION: A previous published version of the preceding paragraph said Avdija had 4 turnovers. He had 2. I used the correct number in the calculation of his usage and efficiency, so nothing about the impact of his efficiency changes. The error was strictly in the text of the article. My apologies for the error.

The offensive rating for each was 69 — that’s 0.69 points produced per possession x 100. League average: 113.8. Wizards average in this game: 116. Warriors average: 124.

How much did their inability to convert possessions into points hurt the team? Well, the league produces 1.138 points per possession. Where Kuzma produced 18 points, average efficiency would have produced more than 29. If we use league average as the benchmark, Kuzma’s inefficiency cost the Wizards 11-12 points in this game. Avdija’s cost them 4-5.

Combined, they used 36 possessions to produce 25 points. That inefficiency cost the Wizards 15-16 points on the scoreboard in this game against the Warriors. The Wizards lost by 9.

Four Factors

Below are the four factors that decide wins and losses in basketball — shooting (efg), rebounding (offensive rebounds), ball handling (turnovers), fouling (free throws made).

I’ve simplified them a bit. While the factors are usually presented as percentages, I often find the raw numbers more useful when analyzing a single game.

Stats & Metrics

Below are a few performance metrics, including the Player Production Average (PPA) Game Score (very similar to the one I used to call Scoreboard Impact Rating). PPA is my overall production metric, which credits players for things they do that help a team win (scoring, rebounding, playmaking, defending) and dings them for things that hurt (missed shots, turnovers, bad defense, fouls).

Game Score (GmSC) converts individual production into points on the scoreboard. The scale is the same as points and reflects each player’s total contributions for the game. The lowest possible GmSC is zero.

PPA is a per possession metric designed for larger data sets. In small sample sizes, the numbers can get weird. But some readers prefer it, so I’m including PPA scores as well. Reminder: in PPA, 100 is average, higher is better and replacement level is 45. For a single game, replacement level isn’t much use, and I reiterate the caution about small samples producing weird results.

POSS is the number of possessions each player was on the floor in this game.

PTS = points scored

ORTG = offensive rating, which is points produced per individual possessions x 100. League average last season was 112.0. Points produced is not the same as points scored. It includes the value of assists and offensive rebounds, as well as sharing credit when receiving an assist.

USG = offensive usage rate. Average is 20%.

ORTG and USG are versions of stats created by Wizards assistant coach Dean Oliver and modified slightly by me. ORTG is an efficiency measure that accounts for the value of shooting, offensive rebounds, assists and turnovers. USG includes shooting from the floor and free throw line, offensive rebounds, assists and turnovers.