There's a lot of strong dynasty analysis out there, especially when compared to five or ten years ago. But most of it is so dang practical-- Player X is undervalued, Player Y's workload is troubling, the market at this position is irrational, and take this specific action to win your league. Dynasty, in Theory is meant as a corrective, offering insights and takeaways into the strategic and structural nature of the game that might not lead to an immediate benefit but which should help us become better players over time.

Better Living Through Betteridge

Betteridge's law of headlines states that "any headline that ends in a question mark can be answered by the word no." It's a commentary on the incentives of publishers-- readers are more likely to read about a surprising result than an unsurprising one, but surprising results are more likely to be wrong.

Is getting a big workload a bad thing for a running back? No. We want backs who score fantasy points. Backs can only score fantasy points when they touch the football. Therefore, touching the football more often is good, not bad. Duh.

Despite the obviousness of this observation, there have been many through the years who would have posited that touching the football more is actually kind of bad. After all, backs can only get injured and wear down when they get hit, and they only get hit when they touch the football.

Since this is a dynasty column, you're probably most familiar with the "touching the football is bad, actually" argument by another name: "mileage". The idea is that running backs are like cars-- they wear down with use and only have a certain number of miles available before everything starts to fall apart. Certain cars are built better than others and good maintenance can extend a lifespan, but all else being equal, if presented with two identical cars from the same model year, you'd expect to get more longevity out of the one that has driven fewer miles.

Sometimes this will be explained using another car-based analogy-- "tread on the tires". Tires have a certain lifespan, and while driving conditions can impact that (driving aggressively in start-and-stop traffic on bad roads will greatly decrease a tire's longevity), every mile they travel brings them closer to the end.

(Confusingly, people tend to get this analogy very wrong. Tread on tires is a good thing-- tires have the most tread when they're brand new, and that tread wears down with use. Yet people will often discount running backs with large workloads because they "have a lot of tread on their tires". It should be that they "have little tread left on their tires", or perhaps "they have a lot of wear on their tires".)

Either way, both analogies operate under the assumption that people work the same way cars work.

Are People the Same as Cars?

Betteridge's law of headlines: no, people are not the same as cars. In fact, they work quite differently.

I've seen a lot of studies over the years that sort running backs by career carries and track how much longer they had left. They all find that the more carries a running back has had, the less time he has left in his career. So mileage is bad, right?

Except if you don't very carefully control for confounding variables, such a study is meaningless. At the most extreme, you wind up in a situation where you're comparing Emmitt Smith at 500 career carries with... Emmitt Smith at 1,000 career carries. Of course, 500-carry Emmitt Smith had more career left in front of him than 1000-carry Emmitt Smith. (Without checking, I'm willing to bet he had exactly 500 more carries remaining after that point.)

For humans, the thing that ultimately predicts decline is age. The specifics vary depending on the field, but every endeavor has a point where participants age out. For something incredibly demanding, like Olympic gymnast, most careers are over by the mid-20s. For a much easier job, like President of the United States of America, we routinely see participants into their 70s or even 80s.

The NFL is no different; different positions have different benchmarks, but everyone eventually ages out. Given that accumulating carries takes time, "career carries" often winds up being a proxy for age, and when one finds that past mileage predicts decline, one is really just finding that older players are nearer the end of their careers than younger ones.

To guard against this, you need to design a study in such a way that you're controlling for age-- comparing players of similar ages but disparate past workloads to see who lasted longer. And every study I've ever seen that controlled for age found that past workload was meaningless (or even slightly positive) for predicting player longevity. I ran down the full list of evidence two years ago.

The inspiration for that article was Rhamondre Stevenson, who was wrapping up an RB8 overall finish in his second NFL season and had seen his dynasty value rise quite high as a result. By the end of the season, he had just edged past Josh Jacobs despite the latter finishing 21st, 8th, 12th, and 3rd in his four NFL seasons, outscoring Stevenson 330.3 to 251.1 in Stevenson's own breakout year.

"Dynasty managers prefer the younger RB" is an unsurprising story, but despite being in the league for two fewer seasons, Stevenson was only 12 days younger than Jacobs. Instead, the reason most managers were taking Stevenson over Jacobs was because they were worried about Jacobs' mileage. He had 1232 career touches to 426 for Stevenson.

Those who worried Jacobs' usage heralded a decline were right; he missed four games in 2023 and his point per game average fell to 14.1. But Stevenson missed even more games and his average was nearly 2 points lower. This year Jacobs has rebounded, ranking 2nd in the NFL in touches and 9th in points per game while Stevenson continues to disappoint. Fortunately, the dynasty community has learned from this error and will never again doubt a running back because he has a lot of mileage.

Just kidding.

RB Ashton Jeanty (Boise) entered today with 651 career carries.

He’s at 21 carries today and it’s only the first half. With at least two games remaining this season, it’s fair to assume he’s going to eclipse 700 carries in three seasons.

It’s not ideal, but not terrible. https://t.co/2B3vMeZ5mS pic.twitter.com/okOYwUIUID

— Dominic White (@DomWWhite) November 29, 2024

Are College Players Like Cars?