Star Player Effects on Teammate Efficiency

I had some fun playing with last night. I promise, it’s not as dirty as it sounds.

Using available data from the last three seasons, I set out to answer a simple question: How does teammate efficiency change when star players are on or off the court? In other words, what impact does the presence of a player have on his teammate’s shooting?

There are a number of players we could do this for, but I wanted to visualize five in particular, four of whom are ball-dominant creators (James, Paul, Harden and Westbrook) and Steph Curry, who is renowned for his court-warping gravity off the ball. Here were the results using players who played at least 1,000 minutes with the player in question, with all five player graphs stacked side-by-side of comparison:


Surprise! LeBron had the largest effect of the group (expected based on more holistic analysis like RAPM. Eight of his ten teammates improved by at least 0.05 points per scoring attempt (or at least 2.5% in True Shooting efficiency). Of the five players who improved by at least 0.15 points per attempt, three played with LeBron. Of course, all the normal caveats apply here as there may be cofounds within the lineups and these numbers aren’t opponent-adjusted. Still, it’s a nice snapshot to have.

Steph Curry had the highest floor (no regular teammate below 1.12) and the highest ceiling (1.34) — no surprise there, as the Warriors have a strong candidacy for greatest offense in NBA history. He also had a hugely positive impact on Kevin Durant this year, who scored at 1.24 per attempt this year without Curry, right in the ballpark of his previous two seasons without Russell Westbrook. (Note that Durant was less efficient alongside Westbrook.) Among star teammates, only Kevin Love (with LeBron) came close to the boost Durant and Klay Thompson experienced when on the floor with Curry.

Finally, I’ve included the individual graphs below for all five players in order to see each specific teammate.