Nylon Calculus: Offensive balance and the Herfindahl-Hirschman Index

The Herfindahl-Hirschman Index (HHI) is a tool used to measure of the size of firms in relation to an industry and an indicator of the amount of competition among them, so one can imagine how valuable such an analysis can be in basketball.

The index is primarily used to judge mergers and acquisitions, per the United States Department of Justice. Examples of HHI in basketball from Nylon include quantifying defensive versatility and lineup density.

Most teams fall under unconcentrated for both points and assists. In this category, most teams are young or trying to figure out their identities. Unfortunately, a lot of these teams don’t have an idea as to what they’re doing, especially when looking at the following graph in the lower left-handed corner:

I arbitrarily nudged the concentrated marking for Points HHI slightly lower to 1200, as it seemed to fit well for where the league split. Teams to the right of the yellow line have 1-2 players that do most of the scoring for their respective teams. Teams above the yellow line have 1-2 players racking up assists while the team above the red line has just one guy racking up points and assists by himself.

The Houston Rockets have a relatively high concentration of points and assists amongst just a couple of players much like the Portland Trail Blazers.  You can also think of the Denver Nuggets when considering well-balanced scoring and passing distributions.

An interesting note’s to be made with how diverging the concentrations were this past year between the San Antonio Spurs and the Cleveland Cavaliers. The Cleveland Cavaliers are a team that revolves around passing from a single player on the floor, while the San Antonio Spurs all work together to funnel the ball to a single player. Not one player in San Antonio averaged more than four assists per game, but the team averaged more team assists per game than the likes of the Boston Celtics or the Minnesota Timberwolves.

On the other hand, it was really only LeBron James who distributed the ball on the Cleveland Cavaliers, leading to a relatively distributed scoring balance. He finished this past season second in the league with 747 assists. To be clear, LeBron was still responsible for a ton of points.

What do distributions have to do with wins? It just so happens that it’s probably important to have a star player at the forefront of the offense:

Having high scoring and assist concentration strongly correlates with wins. In a couple of cases, however, some teams aren’t able to eek out wins with balanced distributions. You’d think a team like the Charlotte Hornets could’ve strung at least forty wins this past year, especially since their concentration mirrors the Miami Heat or the Denver Nuggets.

But maybe that’s the wrong way of looking at this kind of data. The graphs above don’t necessarily tell us anything besides trends and don’t give us important breakdowns like attempts from deep.

Who needs help?

The best players should get the ball the most, unsurprisingly. But when playing basketball, it’s more favorable to have help, so that the best player doesn’t have to be as responsible for generating enough offense to win games. So who desperately needs the most help?

The graph above details the players that have greater than 300 Points HHI and 400 Assists HHI. Besides LeBron James, no other player has any championship hardware. That’s not to say the other players haven’t been successful, it just goes to show what some players go through for just so little.

Take Damian Lillard for example. We saw above that the Portland Trail Blazer offense is moderately concentrated, specifically between Damian Lillard and CJ McCollum. Over the last couple of years, we’ve seen how subpar the organization’s been at getting Lillard talent. In fact, it’s gotten so bad for Portland that the New Orleans Pelicans recognized how central Lillard was to the offense and sent the wolves after him.

It’s obvious as to how little help LeBron James has been awarded over his entire career, so declaring him as a player who most needs help is a cop-out. Given that Giannis Antetokounmpo is still extremely young as a player, and that James Harden has gotten to the Western Conference Finals with a co-All-Star, the player in the NBA that mostly needs help is Damian Lillard.

Wait, what about big men?

For bigs, I’ll take a slightly different approach since most don’t get enough assists to be compared to the likes of primary ball handlers above. I’ve taken some of the players ranking high in Points HHI, and plotted against their effective field goal percentages (looking at players with the highest share of points for their own team while maintaining high eFG%):

This This graph gives us three bigs to look at in LaMarcus Aldridge, Karl-Anthony Towns, and Anthony Davis. It goes without saying that Aldridge could have used help this past season, and it’ll be interesting to see how DeMar Derozan brings Aldridge’s share of points down.

What about Karl-Anthony Towns and Anthony Davis? In actuality, there’s only so much a team can do to take the load off of their respective stars. Is it realistic for the New Orleans Pelicans to stage a coup for Klay Thompson in the next free agency?

These guys have such efficient eFG%, that it might be best for these teams to get Towns and Davis even more attempts from the field in a given game. Surely Towns doesn’t get enough run at only 14.3 attempts per game. Nikola Mirotić averaged 12.7 shots this past season, as a comparison.

For Anthony Davis, his 19.5 shots per game are already a lot, but would it necessarily hurt to get him about four more shots with an effective field goal percentage of 55.2? Here’s how the following chart would look like if the Pels forced Davis to average 32.1 points per game:

You can see Davis shoot up in terms of Points HHI, all else stay the same for the Pelicans. Most of the players above, however, could use a bit more help. They all realize this without HHI, and it’s not surprising when some of these guys get tired of carrying the team every night.