While I’m interested in this exercise – indeed I spent many minutes of my life reading his post on the subject – I have something a bit more rigorous in mind. I want to evaluate whether NBA decision makers have become more skillful at drafting.
Chase Stuart recently looked at this topic in the NFL, finding very little improvement, and my own research on the NFL Draft suggests that the relatively uniform level of skill means that extreme outcomes (e.g., a great draft class, the Browns) tend to be the result of luck.
Methodology
I’m trying to keep this as simple as possible while still being representative. Looking at entire careers is out because every single draft in my 1998-2013 data set features active players. At the risk of underrating a few picks in which the player was a late bloomer AND that late blooming was captured by the drafting team, I will look at the first four years for each player
I am going to use win shares as a proxy for performance. This is due primarily to availability but also because they are a reasonable approximation of performance (though one with known flaws).
Now for the actual measurement methodology, which I feel is refreshingly straightforward. With the benefit of hindsight we know the best player on the board at any given pick. The proportion of the best available pick’s win shares delivered by the actual pick give us the score of that pick.
As an example, Derrick Favors (3rd pick, 2010 draft) accrued 16.1 win shares in his first 4 seasons. The best available player on the board – Paul George, 10th pick – had 29.7 win shares so Favors has a score of 54%. The Pacers' selection of George at number 10 would have a score of 100%. The higher the average score is for a given draft, the better the decision makers are doing selecting the best available player.
Results
We’ll look at the results in three different cuts to see if teams are getting better.
First, are they getting better in the lottery? This is the equivalent of a first round NFL pick, where players are expected to step in and start immediately with a realistic chance of an all-star appearance or two during their rookie deal.
Second, are they getting better in the first round? This has a certain elegance in that each team (barring trades) gets to make their one pick so even if a team is picking 28th, it’s their first shot in the draft and we could expect them to maximize the value of that pick.
Finally, are they getting better across all picks in the draft? It seems logical that we should look at the overall performance of teams at picking players.
Interestingly, the further we go into the draft, the more improvement we see from year to year.
A possible explanation here is that the rigor that used to be applied only to lottery picks has been extended further into the draft. In support of this explanation one could cite the technological progress that allows scouts to see innumerable prospects via YouTube rather than scouting them individually.
Alternatively, the data could be telling us elite organizations continue to pull away from the rest of the league. Those teams that put the best team on the court – and thus pick last in the draft – are now the same teams that have the best process in place to evaluate draft picks. This could come from better evaluation techniques or merely the ability to delay gratification in the case of selecting foreign players who cannot come to the NBA immediately.
I’m inclined to put more stock in the first explanation over the second, but distinguishing between the two is a topic for another day (or for the comments section).
-- For those of you who made it to the end, have a visualization of all picks from 1998 to 2013 with a reference line for best available player:
