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Should he shoot? Looking at the data of selfishness – Part 3

In part 1 and part 2, we looked at selfishness from two different perspectives, one a graphical chart and one a more traditional table. I’ve combined these two visualizations into this single chart. It looks much like the first chart, but an added slider allows you to filter by players’ SE rank. Thus, you can quickly identify, say, the top 10 players in terms of SE without having the leave the visual view. I plan to update this data every once in a while and, when I do, will only present the results in this view.

I’m now going to use these data to make some suggestions about how offenses, specifically the Houston Rockets offense, should operate. My comments are based on a few assumptions.

1. Players selfishness and eFG% are negatively correlated. In other words, the higher a player’s selfishness, the lower his eFG%. This is due to players’ shot selection becoming poorer by taking more shots. Here’s a graphical presentation of what I mean:

The more selfish this player is, the lower his eFG% is

2. The strength of the relationship between selfishness and eFG% is different for each player. Some can take more shots without a huge change in eFG%, while some will see a huge change in eFG% by taking more shots. In math, we would call this the slope of each player’s line. In economics, we would call this the elasticity of each player’s eFG%. Here’s a graphical representation of what I mean:

Can take lots of shots without a large decrease in eFG%

Big drop in eFG% by taking a few more shots

3. Some players are just better shooters than others (or at least shooting better presently). Everything else being equal (i.e., they take the exact same shots under the exact same circumstances), player A will have a higher eFG% than player B. In math, we would call this each player’s constant. Here’s a graphical representation of what I mean:

Good shooter, notice he starts out higher on eFG%

Poor shooter, notice he starts out lower on eFG%






Here’s my premise. An inefficient offense is one in which the players are far apart on their eFG%. This means that, in the team’s current offense, some players have a much better likelihood of making their shots than others at the players’ respective rates of selfishness. In this case, players who are shooting better than others should be more selfish, and players who are shooting worse than others should be less selfish. Thus, a perfectly efficient offense is one in which the players have very similar eFG%s; basically the players would be situated in a near vertical line on the chart. Every team has this theoretical line. Let’s call it the line of awesome. Here’s what it would look like:

Notice how all players are very close to the line of awesome

Where on the x-axis (eFG%) a team’s line of awesome would cross depends on the shooting abilities (constant) of each player. How high or low each player would be on his team’s line of awesome depends on each player’s capacity to absorb more shots without decreasing his eFG% (slope, or elasticity). If players’ are close to their team’s line of awesome, this means that every player is being as aggressive as he should within his own capacity relative to everyone else on the team.

OK, enough jabber. Onto the Houston Rockets. Here’s the Houston Rockets offense from the chart:

The good news is that everyone is actually above-average in eFG% and is kind of close together vertically. In fact, if you compare the Rockets to other teams, the Rockets are doing quite a bit better than most others. Some teams just look completely hopeless. However, the Rockets can still make some improvements.

The two players that appear to be farthest away from the Rockets’ theoretical line of awesome are Harden and Beverley. As it stands, every additional shot that these two take has a less likely chance of going in than an additional shot taken by five of their teammates. So even though James Harden is shooting the ball at a reasonably good rate, it just so happens that his teammates, at their current rates of selfishness, are shooting the ball at an even better rate.

The simply stated solution is for Harden and Beverley to pass the ball more when they touch it. But that doesn’t mean Harden should start passing up fast break dunks. And it doesn’t mean Chandler Parsons should just chuck the ball every time he has it and expect his shots to magically fall. It means that Harden should not take the most difficult shots he currently does, and that Parsons et al should take the least difficult shots that they currently pass up given their capacities and styles of play. So Harden should keep taking fast break dunks, but pass up the double teamed step-back 18 footers that he takes. And Parsons should take the somewhat-contested three-pointer he’s on the fence about.

View this discussion from the forum.

About the author: Richard Li is an independent researcher and consultant. He likes numbers and pictures.

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