Nylon Calculus: The continuing evolution of NBA shot selection
By Ian Levy
You can’t read about the NBA this season without hearing about the increasing prevalence of the 3-pointer and how the shot selection of the league is changing. The focus is always on the 3-pointer, but in reality the changes go much deeper than that.
It’s not just that 3-pointers are increasing leaguewide — 28.9 3-point attempts per team per game this season, the highest in NBA history — we’re also seeing teams focus more on getting the ball to the basket, forgoing mid-range jumpers by going farther and closer to the basket.
The percentage of a team’s true shot attempts that fall in three zones — at the rim, at the free throw line, and behind the 3-point line — have been colloquially referred to as a team’s Moreyball percentage, an homage to Daryl Morey and his norm-busting Houston Rockets.
Moreyball percentage is the measure I used for shot selection in my team offensive style charts. Our own Todd Whitehead noticed that many of the teams this year had seen an increase in shot selection percentile rank this year (since both this season and last season were ranked together). Todd encouraged me to isolate that specific metric from the team charts and offered to build a chart. One doesn’t say no to an offer of graphic assistance from Todd, and so here we are.
Obviously the league-wide surge continues to the be the most obvious takeaway from this graph. Eleven teams increased their Moreyball percentage by at least 15 percentage points this season. Among those are the top three teams in Moreyball percentage this year — the Clippers, Raptors and Rockets — all of whom significantly increased their percentages as a part of dramatic offensive overhauls (or increased emphasis in the case of the Rockets).
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It’s also interesting that three of the top teams in the league — the Cavaliers, Celtics and Warriors — all have seen declines in their Moreyball percentages so far this year. In each case, it’s largely driven by personnel, like the addition of Kyrie Irving in Boston and the increased offensive primacy of Kevin Durant in Golden State. It’s an important reminder of how much symbiosis there is between the skills of a team’s roster and their ideal shot selection. If you have a player who can score efficiently from generally inefficient zones, it becomes less important to hew to an idealized shot selection. On the other hand, if your roster is mostly made up of complementary players without a star talent to bind them together, shot selection becomes increasingly important.