Redefining Offensive Efficiency
When talking about offensive efficiency, most people will reference two statistics: field-goal percentage and now also offensive rating, due to the growing popularity of advanced stats.
The official NBA page gives the following definition for offensive rating:
Measures a team’s points scored per 100 possessions. On a player level this statistic is team points scored per 100 possessions while he is on court
What this means is that a player’s offensive contribution is defined by how much his team scores when he is on the court. So playing for a team that does not score a lot of points adversely impacts a player’s offensive rating. Kyrie Irving is the perfect example. Despite being one of the premier offensive talents in the league, he ranks only 64th in offensive rating out of 242 players who have averaged at least 20 minutes per game this season. This is because Boston is not known for its scoring (19th in points per game) and relies on its defense (tied for 2nd in points allowed per game) to win games.
It would make more sense to try to define offensive efficiency using a player’s individual stats. Players with high field-goal percentages are often considered to be efficient. The idea is that an efficient player is someone who can score more points with less field-goal attempts. That same logic could extend to assists and turnovers. The more a player has the ball in his hands (Touches) and the longer he has it (Time of Possession), the higher his assist and turnover numbers will be. Relevant information could be used to calculate expected values for points, assists, and turnovers. Given that a certain player plays “X” number of minutes and averages “Y” number of field-goal attempts per game, how many points is he expected to score per game? Efficiency could then be defined as the player’s actual value minus his expected value. This could be done for points, assists, and assist-to-turnover ratio.
In the graphs below, actual values for points, assists, and turnovers are shown in color, and the expected values are shown in black.
Expected values for points are based on players’ minutes and field-goal attempts. Scoring Efficiency is the difference between how many points a player actually averages and his expected points per game. Of the 350 players who have played in at least 30 games this season, the table below shows the top and bottom 50 players in Scoring Efficiency.
By this measure, Kyrie is ranked 11th out of 350 players (97th percentile) — which appears a lot more accurate than 64th out of 242 (74th percentile) according to offensive rating. Scoring Efficiency is also easy to interpret. James Harden is averaging roughly 6.7 points better than the expected; Lonzo Ball is averaging just over 4.2 points less than what is expected.
Including only 20-point scorers can show how the best scorers in the game stack up to one another.
The difference between a player’s assists per game and expected assists per game is called Passing Efficiency. The table below shows Passing Efficiency for players who have played in at least 30 games and average at least 3 assists.
According to this, Draymond Green is the most efficient passer in the NBA. His true assist average (7.3) is more than double the expected value (3.38). An article by SI does a pretty good job of summing up Draymond Green’s elite passing ability:
What’s so pleasant about Green, specifically, and the Warriors, in general, is that the ball doesn’t stick…The takeaway here is that Green is making lots and lots of quick decisions, often split-second ones.
Golden State alone has four players in the top 35 of Passing Efficiency: Draymond Green (1), Kevin Durant (13), Stephen Curry (18), and Andre Iguodala (35).
Also interesting to note is that Lonzo Ball in just his first year in the NBA ranks 7th in Passing Efficiency, ahead of superstars like Russell Westbrook and Chris Paul. Even more impressive is that he sits 25 spots ahead of fellow rookie Ben Simmons, who is also considered to be a great passer.
The most efficient ball handlers in the league are the players who have the highest difference between their actual and expected assist-to-turnover ratio. Again, the criteria is a minimum of 30 games played and 3 assists made per game. The table below shows how the players stacked up.
There are players like Rajon Rondo and Lonzo Ball, who contribute very little in terms of scoring but can create easy looks for teammates. They are in a sense “creating points” despite not scoring those points themselves. The full offensive ability of a player includes his ability to score and create (assist). The table below shows 87 players who contribute 20 points per game through either baskets or assists, and ranks them based on how efficiently they do it.
LeBron James is the most efficient offensive player in the NBA. This comes as no surprise considering he combines a rare ability to both score and pass the ball at an elite level.
