Karthik’s Take: Let’s talk NBA shot values

0
371
Charlotte Hornets’ Miles Bridges dunks as New York Knicks’ Elfrid Payton, left, and Julius Randle defend during the first half of an NBA basketball game Tuesday, April 20, 2021, in New York. (Sarah Stier/Pool Photo via AP)

At the most basic level, basketball is about putting the ball in the hoop at a higher rate than your opponent. With the recent analytics boom in the NBA, executives have begun deferring to the mathematics to determine what the optimal type of offense is. This type of statistical analysis is known as a shot value diagnosis. A shot value diagnosis determines the value of a shot by multiplying its value by its probability of going in from various locations on the basketball court through a metric known as expected points per shot (EPPS). This allows teams to understand which types of shots should be taken in the greatest volume in order to maximize offensive efficiency.   

An analysis at Duke University took this idea one step further by factoring in defensive tendencies that shifted based on the shooting threat various players posed. Players were assigned gravity scores based on their spot-up shooting percentages and likelihood to create scoring opportunities from off-ball situations. A gravity score measures how much attention a player draws from the defense. This information was then used to find correlations using linear best fit models between the player’s gravity scores and team shooting efficiency. The researchers ascertained that when players off the ball had high perimeter gravity, it opened up teammates for more high percentage three-point shots. Additionally, players that had higher gravity at the top of the key were able to create more opportunities at the basket in the form of layups and dunks. This data was analyzed using footage from Duke’s 2014-15 NCAA season, but the trends extrapolate seamlessly into the NBA game. In fact, the level of offensive talent at the professional level makes the correlations even stronger, as players there have significantly more polished offensive skill sets on average.  

During the 2018-19 NBA season, given league shooting averages, a three-point shot in the NBA had an EEPI of 1.07 in comparison to a mid-range shot that only had one of 0.81. Unsurprisingly, the NBA has been launching an unprecedented amount of threes. For perspective, “Twenty years ago, 17% of NBA shots were threes. Ten years ago, it was 22%. Five years ago, it climbed to 28%. And it didn’t stop there. The 3-point rate across the entire league kept rising until it soared near another milestone in the first month of this season: It’s settling at almost exactly 40%.” Teams have embraced the analytics boom and attempted to recreate the Golden State Warriors championship model by investing heavily into players that can shoot the long ball in high volume while maintaining efficiency.  

New York Knicks forward Julius Randle, right, defends a shot by New Orleans Pelicans forward Zion Williamson, left, during the second half of an NBA basketball game Sunday, April 18, 2021, in New York. (AP Photo/Adam Hunger, Pool)

Interestingly enough, the EEPI of three-point shots has remained relatively constant in recent years despite the increase in three-point shot attempts. This means the NBA is hitting a ceiling in regards to three-point shooting accuracy. In other words, not everyone can be Stephen Curry or Damian Lillard. The average shooting accuracy from this distance will most likely not reach something absurd to where all other forms of offense become null and void.  

Moreover, while three-pointers have undoubtedly taken center stage, no shot is still as efficient as the slam dunk. Consequently, dunks are also occurring in greater volume than ever before in the NBA’s modern era. After steadily increasing over the past two decades, dunks now make up 15.6% of all two-point attempts, as of 2019. This statistic will increase this season, as well with the way Zion Williamson has joined Giannis Antetnoukoumpo in the paint scoring specialist department. While Williamson has shown the ability to hit an open three, he almost exclusively gets his points in the paint because nobody can stop his locomotive-like 284 pound frame. Many executives and analysts such as Bill Simmons even claim that William’s weight is listed too low and could easily be over three hundred pounds. He currently leads the league in paint scoring with 19.7 ppg, the highest rate of any player since the big diesel’s (Shaquille O’Neal) reign of terror during the Lakers first three-peat in the early 2000s. Unlike Antetokounmpo, Williamson has average height and length. His extraordinary athleticism at that size creates matchup problems for almost every rim defender in the league. The last few postseasons have proved that clogging the paint works to marginally slow down Antetnoukoumpo, who prefers to go over defenders, but what type of personnel can teams throw out to stop Williamson from going to the rim? Teams are simply not equipped to deal with that physically, and it has not only made the dunk William’s signature shot, but also one of the most unstoppable shots in the game today.  

Lastly, an article about NBA shot values cannot ignore the relic that is the mid-range jump shot. This shot was made famous by legends such as Michael Jordan and Kobe Bryant but has quickly lost favor in basketball circles due to its lack of numeric efficiency. As a result, teams are now “donut teams,” who only score from the three-point line, the paint and the rim, according to Celtics legend Ray Allen and others. Some of the best pure scorers in the game such as James Harden and Zach Lavine reflect this idea in their shot charts. However, teams that win championships are still able to shoot the mid-range jump shot at an elite level. This added scoring dimension makes a team significantly harder to guard, and in the NBA finals, a best of seven series where talent is stacked so high, any slight advantage is pivotal.  

Chicago Bulls guard Zach LaVine, left, dunks next to Orlando Magic forward James Ennis III during the second half of an NBA basketball game in Chicago, Wednesday, April 14, 2021. (AP Photo/Nam Y. Huh)

The Golden State Warriors actually utilized the midrange frequently during their dynastic run. During the 2017-18 season, the Warriors scored a ridiculous 1.21 points per shot (pps) in comparison to the league average of 1.11. This included scoring 0.15 more points on every midrange shot attempt they took. While it may not sound like a lot, it was this shooting edge that made the Warriors the offensive juggernaut they were. All three of their best offensive players could hit from every range at a high clip. Kevin Durant, in particular, has made the midrange his specialty and is the only player since 2013-14 that averages better than one point per shot attempt from midrange (1.02). This season, after coming back from his season-ending Achilles injury, he is shooting even better at 1.09 points per mid-range shot, albeit a small sample size thus far.  

Going down the list of NBA champions in recent years, it is evident that every one of those teams was led by stars who shot adroitly shot the midrange. The defending champion Lakers had LeBron James and Anthony Davis; the Raptors had Kawhi Leonard; then there were the aforementioned Warriors; the San Antonio Spurs had their big three of Tim Duncan; Tony Parker and Manu Ginobli and so on. While midrange attempts are never the most efficient type of shot, teams with championship pedigree unquestionably show it is imperative to have midrange threats on any contender’s roster.  

As much as old school fans may hate it, analytics are here to stay in basketball. They have changed the way people look at the game, and I think they  should be embraced. Consulting the numbers won’t mean all threes and basketball will get boring, because the game is always changing. That’s the beauty of NBA basketball. The talent level is so high that teams are always adapting to beat the league contenders and shot values will change accordingly to these roster dynamics. Data driven moves are the future and for players at this upper echelon of basketball competition, every edge matters.  

Leave a Reply