Sharing is Caring: The Spurs, Assists, and the Modern NBA

Welcome back to another installment to the The Professor’s Corner! I am, indeed, a professor. Specifically, I’m a professor and Department Chair. The goal of this column is to bring this wonderful fan base consistent analysis of our favorite team from the perspective of data visualization. I hope each post brings a slightly new viewpoint of the Spurs and the overall NBA.

The Spurs Offense is Improving!

This chart started with a hunch and a question. Intuitively, I felt the Spurs offense has improved through the year (pink lines and shading). But, traditionally, league average offensive rating also increases into the season (grey lines and shading). Consequently, I wanted to examine if the Spurs’ rate of improvement was better than the league average improvement.

Statistical Results: The slopes of the lines in the chart are both significantly different than zero—therefore, both the league and the Spurs are scoring more efficiently. But these slopes are not significantly different than each other (darn you, math), but it’s very close, which means it's clearly something to track through the season.

Since the last “Corner”

Since the last Professor’s Corner the Spurs beat the Lakers (always nirvana), shredded the Pistons (see the two circles at the top right of the below chart)…and then things took a Dejounte Murray-less, downward turn (see the circles on the bottom right). Utah, with the best offense in the league, earned their revenge badge. Memphis, maybe 24 months from being a Western Conference champion contender, offensive rebounded San Antonio to smithereens, and then Detroit’s Saddiq Bey missed 10 3-pointers—but made THAT ONE. A single player summarizes the most recent games. In the last 5 weeks we’ve seen Keldon Johnson’s shooting accuracy soar to the sun and then return to earth—and then burrow far underground to an offensive rating of 65 against the Pistons and 23% true shooting against the Raptors.

There are bright spots! For example, some rabid fans finally found validation for their newly etched Jock Landale tattoos by witnessing him supernova his way to a 73% true shooting. Tre Jones looks like he’s now more than the apple of AppleValley (high school) as he spent December above the Mendoza Line in Estimate Plus Minus (EPM)(1). And, of course, Derrick White is Back! The Commander of the Charge had a 59% true shooting in December despite, (warning, this is weird) shooting 29% from behind the arc. Which means, since he’s a more accurate long-range shooter than his current average, he’s got room to climb further. Overall, the Spurs are better on offense than I anticipated.

Sgt. Pepper’s…Assists?

“What would you think if I sang out of tune?” is the opening line a Beatles song titled, “With a Little Help from my Friends” and a great theme for this installment of The Professor’s Corner(2). Have you heard that the Spurs lead the league in assists per game? It’s true; 28.5 assists per game. Assists are wonderful. They’re an act of kindness, empowerment, selflessness, and a true act of a friend. And since the Spurs get the most of them the Spurs are, quantitatively, the Most Friendly team in the NBA. Book it.

When I think of assists I think Larry and the 1986 Celtics, Peter Carril’s Princeton teams, Magic, Stockton, Vegan CP3, the only thing Jordan didn’t do, the greatest passer in NBA history (he plays for Denver) and many others including the magical 2014 NBA Champions. I see the ball zipping around the perimeter as it transitions from good shot to great shot. Or the extra pass that results in an easier, uncontested layup.

When I think assists I imagine thousands of passes!! Brilliant coaches. The ball gaining energy! The ticket to giving the underdogs a fighting chance! The greatest offenses EVER assembled!

And then…there’s reality. Let’s start with this chart for a baseline.

This chart shows offensive rating for each NBA team in comparison to the percentage of points that are assisted. Although the Spurs have the most assists per game, the Warriors have the highest percentage of assisted points since they shoot more threes via their assists (see, this guy). Denver is 3^rd in the league (see, this guy). It’s clear there are several very good teams with good offenses that produce a lot of assists (Suns, Heat, we-guard-nobody-Hornets, & we-believe-Cavs). Furthermore, there are some putrid offenses in the low-assist quadrant (see left side of chart).

But, if you examine the chart closely, the relationship between assisted points and offensive rating isn’t there. Several very good teams are low in the assist spectrum. Utah, the best offense so far, has nearly the lowest assist percentage. The defending champions and DeMar’s new squad are down in the assist distribution. Atlanta, running point with one of the league’s best passers is not a high assist rate team. The reality is there are great offenses employing different methods to be successful and some use assists more than others.

Historical Comparison: 2014 Spurs

I added THE TEAM to this chart as a comparison. Yep, the 2014 Spurs are on this chart. Can you find them? (hint, bottom right) The 2014 Spurs would have the 2^nd best offense in the league today and nearly the lowest assist rate. Yes, you read that correctly—nearly the lowest assisted percent. That can’t be true?! That team was THE “good to great” team. It was magical and touched by angels! Passing was THEIR thing!

Okay, before you stomp away in anger, I understand reading why the 2014 Spurs had a low assist rate doesn’t sit well with you, That’s why I made this chart…

Passing and Assists

This chart displays the percent of points that are assisted in comparison to the number of passes per possession. Denver, Golden State, Indiana, and Philadelphia throw the most passes. In contrast, Utah, Milwaukee, Phoenix, Brooklyn and Atlanta throw the least (4 of the top 6 offenses). Thus, four title contenders are at the bottom of the league for passes per possession. The Spurs are near the league median; thus they throw an average number of passes but still have the highest number assist per game—a highly efficient pass-to-assist ratio.

I consider there to be five title contenders and only 1 is a “high-pass frequency” team. Thus, it’s rarer for a contender to pass a lot. The Warriors play style, passing more than most, is the exception and not the rule.

Speaking of passing a lot, can you find another pass often team on the chart? Yep, the 2014 Spurs (top left). In fact, despite having a low assist percentage, the Spurs title run threw more passes per possession than any current team in the NBA.

Do the best offenses rely heavily upon assists?

Comparing the 2014 team to the current league helps bring clarity. Watching a Spurs telecast and hearing Bill Land say the Spurs lead the league in assists hasn’t “felt” right to me. Turns out I needed to fix a misconception. I connected the 2014, high-pass frequency, team incorrectly to assists. Additionally, I connected passing and assists to great offenses. In reality, a lot of passing doesn’t always mean more assists. It just means more passes. Furthermore, leading the league in assists and passing frequency isn’t a requirement for being a contender. In the current NBA the opposite is likely true. The best teams don’t throw it all over the gym. Passing, and being a high-frequency assist team, doesn’t represent offensive greatness, it reflects a play style. Let’s use the next chart to address that statement.

This chart displays the relationship between pick & roll frequency and passes per possession. More accurately, it displays the INVERSE relationship between these two variables. Teams that run a lot of pick & roll pass the ball less. Utah and Atlanta are prime examples, and, for the opposite reasons. Atlanta has Trae Jones, an incredibly skilled scorer and accurate passer. The defensive attention he requires facilitates success for the roller(s). Thus, 2 of the top 15 leaders in dunks this season both play for the Hawks—Clint Capela & John Collins.

Utah has Rudy Gobert; a deceptively mobile big with a 9’9” standing reach. Both Trae and Rudy are defensive nightmares that require help. Utah leads the league in points per possession from pick & roll sets and it’s primarily due to Rudy being a human cheat code. His rolling to the rim momentum MUST be impeded or he’ll dunk it every play— this is 4^th consecutive season of him leading the league in total dunks and he also has NBA single season record (306). But it’s not just the dunks. Slowing his rim momentum often requires defensive help. A defender is forced to leave his man, from the perimeter, and that’s where Utah employing 6 rotation players shooting at, or above, league average from behind the arc produces a 118 offensive rating. Since pick & roll sets are time consuming, and a good shot is hopefully 1-2 passes away, the teams that run this action often don’t pass less than others.

Spurs Comparison Stat:

• The Spurs and Jazz 6 players shooting greater than league average from 3.
• Those 6 Jazz players have launched 1,147 3-pointers.
• Those 6 Spurs players have launched 539 3-pointers.

Another offensive set that doesn’t involve much passing (actually, zero) is isolation. And it’s isolation frequency that makes the bottom left of this chart is VERY interesting. The Bucks and Nets are both low pass frequency AND low Pick & Roll teams and, as you can see via the circle color. Moreover, they are both high isolation frequency teams (Nets lead the league). This is logical since the Bucks have Giannis and the Nets have Durant. Why risk throwing oodles of passes when your guy can get himself a great shot without all that gestalt selflessness?

In contrast, the Spurs don’t do isolation—easily the lowest in the league. But they’re in the top quarter in pick % roll frequency with 25%. That frequency feels higher since you must consider that nearly 1/6th of the Spurs offense comes in transition (3^rd in the league) (3). Thus, when running a half-court set, you’re seeing lots of pick & roll.

Are the Spurs good are pick & roll? Eh, not really. They’re 20^th in the league in points per shot from the ball handler perspective and 15^th in the league

from the perspective of the roll man. Wait, does that makes sense? The Spurs have an above average offensive rating, but they’re not awesome at frequently used pick & roll, how is that possible? Let’s go full circle, cue up the 2nd track in Sgt. Peppers Lonely Hearts Club Band, and….

Get a Little Help from My Friends:

Assists, Dear Sir: Our scrappy Spurs find ways to make it happen! San Antonio attempts to score off cuts using the 4^th highest frequency in the NBA. They also have the 2^nd highest frequency for handoffs…and the 6^th highest scoring attempts off screens. They’re doing work out there! And with no dominant isolation scorer none of that work is happening alone. There’s a reason the Spurs lead the league in assists. They have to. They don’t have a player that can do it alone, so they require each other to score. They need the help of their friends and I’m okay with that. It feels right. A lesser organization would do this differently.

---

Notes/Asides

1. EPM (Estimated Plus Minus) is a very respected advanced metric for the NBA. It is available on dunksandthrees.com, but the data is not free to the public.
2. When I originally typed these lyrics, from memory, I typed “What would you do...”. Which was actually wrong. Strange mistake, but there’s a reason. I learned the song from the opening credits of the TV show, The Wonder Years, in which Joe Cocker’s version started with “What would you do...” In the original version John Lennon sang, “What would you think...”
3. 3rd in the league in transition come from cleaningtheglass.com .