Nylon Calculus: It’s not small ball, it’s skill ball

Has the NBA actually gotten smaller? Or have players just become more skilled? A few weeks ago, Kevin O’Connor wrote for the Ringer:

"“Small ball” is the usual name for today’s preference toward fast, 3-heavy, and switchy, but several NBA executives told me “skill ball” is a better descriptor."

The term small ball has become so ubiquitous it’s interesting to think about whether it accurately describes the modern trends. Now, of course, smaller could refer to weight and as Paulo Uggeti of the Ringer explored recently, players have been cutting down their weight. However, it’s generally thought that when you refer to smaller, you refer to a player’s height. The question becomes, are NBA teams actually giving minutes to shorter players, relative to others at their position? Or have we been using a poor descriptor for the recent NBA revolution towards fast, switchy players who can shoot?

We can measure this by looking at the average height of the NBA rotation player over time. We’ll define the NBA rotation player as someone who has played at least 1000 minutes within a season. This isn’t perfect since we can’t account for rotation players who get injured and therefore play less than 1000 minutes (i.e. Joel Embiid) but we’re at least not including anyone who isn’t a rotation player since we’re keeping our definition overly restrictive.

First, let’s look at all NBA rotation players without adjusting for position.

As we can see here, the average height of the rotation player has remained pretty constant over the last 20 years (wHt is simply height weighted for minutes so the players who play the most minutes will be weighted the most). But of course, no one is arguing that point guards or shooting guards have gotten smaller. The argument revolves around swings (players who can play the 3 and 4) and big men (players who can play the 4 and 5).

So we can look at the average height for all small forward, power forward and center rotation players. And just for fun, we’ll also look at the average height for Point Guard and Shooting Guard rotation players as well.

As we see here, none of the positions have gotten smaller. In fact, the average height of each position has remained pretty constant over the last 30+ years (most of the graphs generally fall within an inch and we don’t see any wild fluctuations). Point guards and small forwards have actually gotten slightly taller in recent years.

So why do we call it small ball? Players aren’t really any smaller than they were 20 years ago. In fact, a player such as Giannis (6-foot-11 according to Basketball-Reference) is taller than the average power forward throughout history (6-foot-9) and on par with the average Center throughout history (6-foot-11) and yet when Giannis is played at center or even power forward, we consider it going small.

As I mentioned earlier, this labeling definitely has to do with a player’s weight. Giannis is objectively taller than Dwight Howard but he weighs about 40 pounds less. But then why don’t we call it skinny ball? Because to some degree, height does matter. For example, Clint Capela is routinely listed as the center in every lineup and yet according to NBA.com, P.J. Tucker actually weighs five more pounds (or another one is in Washington where Markieff Morris weighs five more pounds than Marcin Gortat who is always listed as the center). So skinny ball doesn’t seem to be a better term.

Next: Nylon Calculus -- An early look at rookie shot charts

Skill ball seems like the most appropriate term given that teams ideally want all five players to be able to dribble, pass, shoot and switch (in a future post, it’d be interesting to explore how these skills have changed by position since 2013-14 using the player tracking data). And it adequately describes how the NBA has changed.