Kevin Durant, xPTS and the question of how much winning impact can Elite Tough Shot Makers have?
Good morning, y’all.
Recently wrote a paper introducing a new metric called xPTS, which essentially quantifies shot quality by measuring the expected value of each field goal using:
Shot location
Shot family
Possession context (I.E: Transition, Second Chance, Halfcourt, etc etc)
Actual defender distance
A dunk at the rim with a defender 2-4 feet away is worth 1.88 points, a cut to the rim from 2-4 feet 1.47, a driving layup with 4-6 feet of space 1.43, a contested layup at 2-4 feet 1.27, and a smothered shot at the rim with a defender inside 2 feet just 0.55, with the league average PPP being 1.09.
With expected points, you can do a lot of cool things, such as:
Even cooler, you can measure how a player’s presence bends his team’s offensive and defensive geometry, and its chance creation on both ends, a different flavor of regularized adjusted plus-minus.
xpts rapm: a player’s regularized on/off impact on their team’s shot diet and shot quality as well as suppress the opposing teams’ shot die-in shot quality
conversion rapm: a player’s regularize on/off impact on their team’s ability to make and suppress shots above or below expected
His net xPTS-RAPM is a very interesting story, especially when you pair it with his conversion.
He ranks in the FIRST PERCENTILE, as in his presence contributes to one of, if not the very worst, shot diet and chance creation in the entire league.
His shot-quality impact is among the single worst in the entire league. He provides no rim pressure, there is no transition game, the offense becomes a half-court jousting match every possession.
His influence turns his team into a midrange engine, the quantified worst shot in basketball, at roughly 7% more than league average.
He still rates well in all RAPMs and off metrics, because he is, even at his age, among the most elite converters in the sport.
He ranks in the 99.8th PERCENTILE in conversion RAPM. When he is on the floor, his team’s offense converts far more than the chance created would predict. (Even with his average defensive conversion impact)
A whopping 270 points above expected this past season, a bigger gap between him and 2nd Place (Jokic) than between 2nd and 5th.
He makes the poorly graded 8-to-10-foot pull-ups at about 1.21 expected points, versus a league average of 0.94.
Functionally, making what is graded as the worst shot in basketball worth more than a three-pointer taken from the average NBA player.
His total on-court impact is shown thorugh :
Net RAPM, the additive sum of xPTS-RAPM and conversion RAPM, which is to say, a pure RAPM with no prior, just basic regularized adjusted plus-minus, where he ranks in the 83rd percentile
ARC (Adjusted Regularized Contribution), a possession-weighted, box-blended impact, has him in the 92nd percentile
Houston is 3 points better on offense with him on the floor, minus 2 in total due to defense.
My question is, even with his positive impact on Houston’s offense, which isn’t the most spaced or geometrically balanced, is this the level of shot-making required to have a positive impact when your shot diet is this bad?
It reminds me of a lot of the conversations around DeMar DeRozan and how much of a winning player he is. He has a similar level of poor shot selection with his usage, which bent the whole team’s geometry into less efficient and effective shots. He did not have anywhere near the shot-making lift.
Even with this shot-making lift, is it not a self-fulfilling prophecy that there is a limit to how big of an offensive impact a “tough” shot maker can have?