The first principle is that you must not fool yourself – and you are the easiest person to fool.- Richard Feynman
For an engineer like me , unintended consequences are a way of life. Someone comes up with something fancy and we see some new way to apply it. Getting from point A to point B is the goal but somehow serindipitously we wind up at point X.
Let me explain. You may have noticed that it’s getting a little crowded in this space. This is all prelude. We are working on something. As part of that, I’ve been going thru some projects I had pending. One of them was continuing to breakdown and reverse engineer all the advanced stat models out there. I finally finished most of that this weekend and I will be writing it up at some point in the future.
But this post is not about that.
It’s about this:
Usage Percentage (The percentage of a teams plays a player uses while he’s on the floor): 100 * ((FGA + 0.44 * FTA + TOV) * (Tm MP / 5)) / (MP * (Tm FGA + 0.44 * Tm FTA + Tm TOV)).
And maybe a little of this:
Before we get too crazy here, feel free to go to the Basics for background. The numbers are courtesy of Nerdnumbers and all the stats,tables and madness that follows is based on 2010-2011 data for the NBA thru 03/26/11.
Let’s get started with some background:what’s usage and what are usage curves? Usage is the % of the available offensive possessions a player uses when he’s in the game. Usage curves come from Dean Oliver’s Basketball on Paper (which I may or may not have spent an inordinate amount of time perusing recently).In chapter 19, Oliver goes over “skill curves” that plot a player’s offensive efficiency when compared with usage . In the book, he does this on a player by player basis to show that players who take fewer shots become more efficient and as they take more shots their efficiency drops. He doesn’t quite explain this other than with some hand waving voodoo magic which is something that could be frustrating to someone who was trying to understand what he was doing and trying to …. Really need to stop with the inner monologue.
So anyways, the theory, based on Dean’s skill curves (or usage curves) goes goes as follows:
- Certain players need to take all of the shots because their teammates can’t
- There are diminishing returns on shooting. Taking lots of shots is not easy, the more shots you take the harder it gets.
- Each player has an optimal range of shooting and players like Kobe are good with 15-25 shots a game but other players wouldn’t be.
The usage argument boils down to teams need a guy (like say Melo) to take shots (i.e. become high usage guys) and that this is the way to succeed in the NBA.
High usage is a high risk strategy for the most part. We want a good spread going to players who are at above average at the needed usage.