Dynasty, in Theory: Most Comparisons Are Wrong

Photo: Joe Rondone, USA Today Sports

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There's a lot of really 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, 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.

Most Comparisons Are Wrong

Fantasy football has exploded in popularity over the last 20 years, which is good for me (a person who writes about fantasy football) and for you (presumably a person who likes reading about fantasy football). With that rise in popularity, there's more content than ever before. Some of it is weird and unlike anything else (it probably comes as no surprise that I'm a big fan of the weird stuff). But a lot of it takes on a predictable pattern. One major genre of analysis is what I like to call "Finding This Year's X".

Here's how it works: last year, several players dramatically outperformed expectations. If you rostered one or more of those players, you had a much higher chance of winning your league. This year, players will (probably) once again dramatically outperform expectations, and since we (presumably) would like to have a much higher chance of winning our league, these pieces compare current players to last year's league winners to try to find this year's league winners.

Winning your league is a fine goal, but the problem is that this genre of analysis will rarely help you accomplish it. That's because most of these player comparisons are wrong. I don't mean that in a general sense-- as in "all player comparisons are wrong" (but some are useful). For example: if you compared Justin Jefferson or JaMarr Chase to all receivers who had massive rookie years, your pool of comparable players would include Randy Moss. If Randy Moss had ruptured his Achilles tendon in Year 2, that would make the list of comparable players to Jefferson or Chase look worse. But Randy Moss rupturing his Achilles (or not) in 1999 doesn't actually make it any more likely that Ja'Marr Chase would rupture his Achilles (or not) in 2023.

Any time you compare a player to a list of different players, that comparison is, by definition, wrong (since those other players are not actually the player in question). But it can be useful if, for instance, players who have monster rookie years tend to have broadly similar career shapes (they do).

Anyway, that's not the piece I'm writing today-- mostly because I already wrote it six years ago. Instead, today I want to argue that these player comparisons usually make a fundamental error that ensures that not only are they wrong, they're unlikely to even be useful.

How Most Player Comparisons Work

The typical first step in a player comparison is finding a past league winner you want to compare. For our purposes, let's say 2021 Cooper Kupp. In 2021, Kupp was a middling receiver who had a massive, out-of-nowhere breakout at age 28 to finish with the second-most receptions and receiving yards in history (along with 16 receiving touchdowns). Obviously, if we can find the next middling receiver who will rewrite the record books, that is a huge advantage. So comparisons will look for relevant attributes that would have predicted Kupp's breakout and then search for those attributes in other receivers.

For instance: Kupp was written off in part because he was primarily a slot receiver and slot receivers are typically assumed to have lower upside. So maybe in searching for this year's Cooper Kupp we pay special attention to slot receivers. Kupp was playing with a new quarterback in 2021, the well-regarded Matthew Stafford, so maybe let's look at receivers with a new passer. Despite the low regard in which he was held, Kupp had a Top 10 season two years prior, finishing with 94/1161/10 receiving.

So we're looking for a 28-year-old slot receiver playing with a new quarterback for the first time in his career, coming off of a disappointing season after a Top 10 age-26 campaign in 2021. Therefore, this year's Cooper Kupp is... Hunter Renfrow (whose 103/1038/9 performance in 2020 looks eerily similar to Kupp's 2019).

Now, having said all that, I want to make it clear: despite the superficial similarities, Hunter Renfrow is not, in fact, a secret league winner for the 2023 season. (Well, he's probably not; he's about as likely as any other player being drafted in a similar range, I suppose).

Why does that process not work? I want to focus on three key problems.

Problem #1: Most Years Don't Have a "This Year's X"

Who was last year's Cooper Kupp? Tyreek Hill, maybe, or A.J. Brown? But both players had a stronger history of production, were being drafted in the first three rounds, and were considered the top receivers on their own team (none of which was true for Kupp in 2021). Christian Kirk? He had the most similarities as a player, perhaps, and his 84/1108/8 was certainly a nice surprise, but he wasn't exactly a league winner (he scored just 56% as much as Kupp had the year prior).

For that matter, who was 2020's Cooper Kupp? if Cooper Kupps are so common, then why were we surprised by him in the first place?