How Age Affects Average Draft Position, Career Value

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Age is not just a number when it comes to the NFL draft. Of all the data on a scouting report, the real difference-maker when it comes to predicting NFL outcomes may instead be found on birth certificates.

Quite simply, the younger you are, the better. This is hardly a surprise for people who follow prospecting in Major League Baseball, where performance leading to The Show is always age-adjusted. And it’s been well known for a decade how important draft age is in predicting NBA outcomes, with, of course, younger being much better and older far worse.

Here’s the data on draft age in the NFL (age is as of September 1 of their draft year). We’re using Pro-Football-Reference.com’s weighted career approximate value (CarAV), which rewards a player for his contribution to a team’s points scored and prevented as well as overall performance in other key statistics. CarAV is normalized so that the position of the player does not matter. This is all first-round picks this century selected through 2016 so that everyone is graded for the entirety of their rookie contract.

You can see that NFL teams prefer younger prospects, as age 20-21 players (only a handful were age 20 on 9/1 of their draft year) have the highest average overall pick. That steadily declines with age, with older players being taken on average later. This is a very rational process given that CarAV is highest the younger the prospects are and steadily declines with age. The difference between a 21-year-old and 22-year-old prospect is tiny, but it’s significant when choosing between a 21-year-old and 23-year-old prospect. If teams are grading a younger prospect similarly and even slightly worse than an older one, the younger one is likely to end up being the better performer. 

There are a couple of likely reasons for this. Foremost, younger players are more likely to continue to improve. Remember, with many prospects the difference in age is as great as two full years or more. The other, less obvious reason is that the college performance being graded by scouts is less meaningful if the prospect is three years older than the player he’s competing against. Take the film of BYU offensive lineman Brady Christensen, who is nearly 25. Shouldn’t Christensen be dominating 20-year-olds? He’s a grown man.

Yet age is rarely mentioned in forecasting the expected order of NFL draft picks despite there being exponentially more interest and analysis of the NFL draft than all the other league drafts combined. Last year, Joe Burrow was one of the oldest QB prospects but was still unquestionably the No. 1 pick. (Note he was significantly outplayed by a much younger prospect, Justin Herbert, taken five spots later).

Ironically, despite top-overall pick Burrow being completely forgiven for being very old for a rookie QB, NFL teams were more age-obsessed in the first round of the 2020 draft than ever before. A record 22 age-21 players were drafted. The next highest year was 2018 (18). In the past 10 drafts, the average number of first-round prospects age 21 or younger is 12.3. 

Note that the pool of underclassmen has grown, too. In the period, 88.9 underclassmen have declared on average, but the range is 61 in 2011 to 118 in 2020. This year, according to the NFL, it’s 98 underclassmen who have declared. 

Since being a 22-year-old prospect on September 1 is effectively neutral, there just are not that many players projected by many to be first- or second-round picks who should be flagged for being too old or starred for being quite young. Here’s the complete list by position:

How can this be leveraged in the props market? Let’s look at Najee Harris. He’s the favorite to be the first RB taken. But if teams are prioritizing age, as they seemed to be doing just last year, then Harris may be downgraded on many boards. The player who is most likely to be upgraded for his age, Javonte Williams, is a significant underdog to be the first RB drafted. (Note that while Williams was clocked at a below-average 4.55 at his Pro Day, Harris chose not to run).

Perhaps the best relevant prop for age-based analytics is over 4.5 WRs drafted in Round 1. Youngsters Terrace Marshall Jr. and Rondale Moore generally have a second-round ADP, but if teams adjust their grades upward for their youth, then they could unexpectedly sneak into the first round and put that prop well over the expected total.