No league for old men

Back in December of last year I went through some calculations with the data set I stitched together including both performance and salary data. You can check the post out here for a series of simple graphs that go a long way toward explaining team behaviors and why certain things are the way they are in the NFL, particularly as they relate to player tenure and performance over time.

As I was reading through that post again recently, however, I was struck that it makes the implicit assumption (explicit above) that things are the way they are. What I mean is that this data is the average over a period of time, while there may in fact be some trends to observe by looking at the period year-by-year.

Charts

The average age of all NFL players[1] fluctuated between 26.5 and 27 for most of the post-1994 period (the salary cap era) before dropping from 2008 through 2013 almost without interruption. Applying a weight based on games played or games started, the other two lines on the chart, indicate that the pattern is consistent for the starters as well as the backups. NFL rosters are roughly half a year younger than they were from 94-08.

Are NBA teams getting better at drafting?

Looking back at the NBA Draft one can find some pretty egregious mistakes. Bill Simmons recently took a look at every NBA draft since 1995 and reordered them based on where his evaluation of the players’ careerssuggests they should have gone.

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[1][2].

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 (3^rd pick, 2010 draft) accrued 16.1 win shares in his first 4 seasons. The best available player on the board – Paul George, 10^th 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 28^th, 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:

Learn About Tableau

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[1] This is also based on the current structure of rookie contracts. There are team options for the 3^rd and 4^th year, as well as a qualifying offer that can give the team the right to match any offer made to the player for a new contract beginning in their 5^th season. To make sure we still have a usable, relatively current data set, we’ll use the first 4 seasons.  

[2] It’s probably not ok, from a style guide perspective, to go with double footnotes, but this is about a different thing. An acknowledgement here that several foreign players selected in the draft in the years we’ll be using are either still not in the NBA or have not yet finished their first 4 seasons. Not much can be done about it but it likely makes some late 1^st round and 2^nd round picks look worse than they are. Those teams took a defensible shot with their picks and either couldn’t convince the player to come over or knew there would be a couple years before they would move to the NBA.

Why didn’t the Browns draft a wide receiver?

Less than 24 hours after trading down to grab some extra picks and then trading back up to grab Johnny Manziel the Factory of Sadness got cranked up again and word leaked that Josh Gordon, Cleveland’s All Pro wide receiver, had failed a drug test and would be facing a full season suspension. As someone who grew up in Cleveland let me just say that none of this was surprising.

What WAS surprising to some people was that the Browns, holding the 3rd pick in the 2nd round, didn’t draft a WR there. Not only did they not draft one at the 35th pick, they didn’t pick one through the rest of the draft.

In the medium- to long-term the Browns will certainly need some help at WR now that it seems they can’t count on Josh Gordon. For help with this season, however, the draft pick would have almost certainly been a non-factor – especially after they passed on Sammy Watkins and Mike Evans in the first round. 

Average 1st Season AV by Round Drafted

Position	1	2	3	4	5	6	7
C	4.0	2.9	1.2	1.9	1.2	0.4	0.6
DB	4.3	3.1	2.0	1.4	1.1	1.0	0.9
DE	4.7	2.1	1.6	1.5	1.2	0.5	0.7
DT	4.0	2.1	1.5	1.1	1.1	0.8	0.5
G	4.1	3.0	2.1	1.6	1.1	0.9	0.9
LB	5.9	3.6	1.9	1.4	1.0	0.8	0.8
QB	3.8	2.3	0.6	1.2	0.3	0.4	0.2
RB	6.7	4.2	2.7	1.9	1.1	1.2	0.4
T	5.2	4.6	2.0	1.4	0.8	0.7	1.2
TE	4.1	3.3	1.9	1.8	0.9	0.9	0.7
WR	5.2	3.1	1.6	1.4	0.7	0.3	0.5
Total	4.9	3.1	1.8	1.5	1.0	0.7	0.7

 
The fact that the Browns drafted a T at the 35th pick seems even better with the immediate need for help on the line and ability of tackles to contribute right away. WRs in the first round show strong performance, but those in later rounds underperform the average 1st year AV.

For reference, the averages for different levels of performance are:
 

Highest Performance	Avg AV
AP	13.6
PB	11.1
Starter	6.6
Roster	1.4

 
Finally, the list of wide receivers to deliver more than 10 units of AV since the 1994 draft is relatively short and heavily weighted to round 1. For most of the 20 years in the data set (11, to be precise) there are 0 receivers who reach 10 AV. There are 11 picks in the other 9 seasons who hit that threshold (Josh Gordon had 11 in 2013):

 

Year	Pick	Player	Tm	AV1
2013	76	Keenan Allen	SDG	10
2011	4	A.J. Green	CIN	10
2011	6	Julio Jones	ATL	10
2009	22	Percy Harvin	MIN	12
2006	252	Marques Colston	NOR	10
2003	54	Anquan Boldin	ARI	10
2001	36	Chad Ochocinco	CIN	16
1998	21	Randy Moss	MIN	17
1996	7	Terry Glenn	NWE	13
1996	18	Eddie Kennison	STL	10
1995	8	Joey Galloway	SEA	12

None of this means that Cleveland doesn’t need some help at WR. The Browns’ GM Ray Farmer knows it’s an issue and is likely looking at a number of different options including free agents. The fact that he passed up the crowd-pleasing WR pick to stay true to where he and the Browns’ front office team had players slotted should encourage fans that he has a strong process for finding the necessary support.