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Creating a NFL draft value chart, Part I

Nearly five years ago, I came out with my own draft value chart to replace the “Jimmy Johnson” draft chart commonly cited by draftniks. What I did then was assign the career approximate value grade to each slot for each player drafted over a 30-year period, smoothed the data, and came up with a chart that actually represented career production.

The chart was due for an update in any event, but I’m going to make a key change. Using each player’s career AV makes sense on some level, as the drafting team gets the chance to have a player for his entire career. But the real value in the draft –especially now thanks to the new collective bargaining agreement — is the ability to get a player for cheap on his rookie contract, which expires after (at most) five years. The Jets got a great deal with Darrelle Revis early in his career, but now that he’s the highest paid cornerback in the NFL, much of his value (even pre-injury) is gone.

There’s also another consideration. Of the 100 top-ten draft picks between 1998 and 2007, only 48 players [1]counting Eli Manning and Philip Rivers as staying with the teams that drafted them were still on the same team entering their sixth season. From the perspective of the head coach, things look even bleaker. In only eleven instances were the head coach and the top-ten pick still on the same team after five years (i.e., in year six): Chris McAlister and Jamal Lewis with Brian Bilick in Baltimore, Donovan McNabb with Andy Reid in Philadelphia, Richard Seymour with Bill Belichick in New England, Julius Peppers and Jordan Gross with John Fox in Carolina, Carson Palmer with Marvin Lewis in Cincinnati, Eli Manning with Tom Coughlin in New York, A.J. Hawk with Mike McCarty in Green Bay, Mario Williams with Gary Kubiak in Houston, and Levi Brown with Ken Whisenhunt in Arizona.

If you’re a head coach — or a general manager — I’m not sure it makes sense to project any more than five years down the line. Therefore, I’m going to construct my draft value chart based on the amount of Approximate Value provided by that player in his first five years after being drafted. [2]Note: I am giving the player credit for all of the AV he earned, regardless of whether or not it was accumulated with the team that selected him. Using PFR’s AV as my guide, I graded each player drafted from 1980 to 2007 and counted how much AV they accumulated in each of their first five years. Below is a chart plotting the data along with a smoothed line:



How does that compare to the NFL draft value chart? Before we can do that, we need to make one adjustment. The NFL draft value chart was designed to measure the marginal value of a pick or a player, while AV measures total value. In the draft, the last pick has only negligible value; however, even undrafted players would be expected to have accumulate some AV. So in order to to make the AV chart measure marginal value, I am going to subtract 3.6 points from each draft slot (that’s because the last slot is worth 3.7 points of AV). You can view these marginal values for the first 224 draft picks here.

In order to place the NFL draft value chart (which goes up to 3000 points) on the same graph as the AV value chart, I am going to measure each pick as a percentage of the total number of points given in each system. In the NFL draft value chart, the first pick is worth 3,000 points, while all 224 picks are worth a total of 60,684 points. As a result, the first pick counts for 4.9% of the entire draft value, compared to just 2.1% in this modified AV system:

As you can see, the charts look pretty different. According to the AV graph, the top picks are significantly overvalued relative to the middle round selections. It’s hard to know what’s “right” when designing a draft value chart, but the results here are pretty interesting. I agree with Brian Burke’s theory that draft picks are more like gladiators than bricklayers; there are only so many slots on a roster and so many starters, so you can’t simply look at value in a vacuum. I’m not sure the above chart would tell me to automatically trade down and get second and third round picks if I was running an NFL team. Still, it’s hard not to ignore how sharply the NFL draft value chart drops off, which doesn’t bear much resemblance to reality.

Before I move on to Part II, I’d like to hear your thoughts.

References

References
1 counting Eli Manning and Philip Rivers as staying with the teams that drafted them
2 Note: I am giving the player credit for all of the AV he earned, regardless of whether or not it was accumulated with the team that selected him.
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