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Dynasty Spotlight: Shapley Value in Dynasty Trades

By C. H. Herms | Updated on Tue, 28 Nov 2023 . 9:18 PM EST

How You View Your League Can Shape Your Trading

How much do you know about Lloyd Shapley?

Never even heard of him?

Well, you'll want to read to the end of this one, because he just might be the key to turning around your dynasty roster.

Let’s look at how Shapley and cooperative game theory can help you make better dynasty trades.

What Is Cooperative Game Theory?

Let's start with game theory, which can be a pretty complex and wide-ranging field.

For our purposes, here's an overly simplified version: Game theory looks at the interaction of decisions and actions by participants in a competitive situation to optimize your decision-making.

There is cooperative and non-cooperative game theory.

Cooperative game theory deals with scenarios where people can benefit by coordinating their actions, forming relationships, and then analyzing how groups function effectively to accurately assess each participant's contribution.

This theory has many more applications, from socioeconomics to biology. But the goal here isn’t to make you an expert on the subject.

Think of your dynasty league as an ecosystem of managers you get along with to reach your goal of winning a title.

Cooperative Game Theory In Dynasty

Because there’s only one winner every year, you could argue that fantasy football falls under the non-cooperative umbrella.

But winning a dynasty title is difficult without having a good relationship with the other people in your league. You have to be cooperative on some level. Open dialogue with your league mates is a cornerstone of this format.

On top of that, everyone’s timeline doesn’t necessarily align. 

Some of you are actively tanking, rebuilding, or contending at any given time. And each manager makes a different contribution to your league.

Looking at your league in this way can allow you to assign a value to each manager and their players.

Shapley Value

Nobel Prize-winning economist Lloyd Shapley introduced his namesake concept in 1951 as a way to assign these values through different “axioms” or accepted truths.

In his version, an actual mathematical formula determines values. That’s not what we’ll be doing here.

Assigning a “true” Shapley value to any individual player or manager isn’t a concrete practice because dynasty, and fantasy football in general, is an ever-changing landscape of unpredictable outcomes.

But you can apply the Shapley value by coming up with an approximate measure of each player's marginal contribution to every possible combination of dynasty teams they could be a part of.

How? Let’s dig in …

Applying Shapley Value

First, define what’s important to you. Does your team need players who score points right now or flexible assets like rookie draft picks to spend later?

Finding a manager in your league with the assets you want from there is easy.

After that, determine a player’s or pick’s marginal contribution. Each asset’s contribution is determined through what is gained or lost by removing them from the game (i.e., their skills, fantasy points, long-term/short-term outlook balance, etc.).

Obviously, this varies based on which competitive window you’re in and what sorts of assets the other manager has to offer.

Say you’re a contending manager, and you want a stout WR in his prime who adds 17.5 PPR points per game to your lineup and should sustain that production for the next few seasons.

The rebuilding manager wants your young RB, who only adds 12 points now but has the potential to deliver 20 per game in a year or two.

The WR’s marginal value is +5.5 now and possibly -2.5 later. If you aim to win now, you’re not losing that much value by sacrificing 2.5 points in a year or two. Generally, this is a good deal for both sides.

This sample trade uses the detailed analysis from our Trade Navigator to show how trading Buccaneers WR Mike Evans for Titans RB Tyjae Spears will likely hurt the Spears team this year ... 

... but help it in the longer term.

Avoiding Trade Pitfalls

One axiom of Shapley value is that interchangeable players bring equal value.

George Pickens and Christian Watson are basically equal assets. Each player is an athletic outside WR who has been inconsistent to date and plays with a shaky QB. Both even got drafted in Round 2.

You’re welcome to pick your favorite between them. But trading either for the other isn’t likely to accomplish much.

Another axiom says dummy players hold no value.

You can load up a trade calculator with a bunch of players who add up to “fair value” in a 6-for-1 trade for Josh Allen. But why would the other manager want a bunch of bench players who add little to no value weekly in exchange for one of the best fantasy QBs?

That’s like trying to trade spare engine parts for a motor that already makes the car run. The Shapley value in this situation is not great.

Such severely lopsided offers will almost always get rejected, and it won’t help your chances of dealing with that other manager in the future.

Now Go Put it to Work

There's no theory or formula that will guarantee every trade's a winner. All sorts of unpredictable things happen constantly in the NFL.

But understanding how to look at the other teams in your league, their motivations, and how asset values differ by team will definitely sharpen your trading.

You can better appreciate the direction your team is headed and make more innovative, strategic deals through the concepts of Shapley value:

• Put yourself in the other person’s shoes. 
• Don’t be afraid to “lose” later when you can win now.
• Never be the jerk who tries to fleece someone else.

Keep these ideas in mind to sustain your fantasy success.

Dynasty Goal: Never Rebuild

You can probably find rebuilding teams in your dynasty league every year. But our primary goal is to never reach the point where you need to rebuild. Jared and Matt discuss how to do that in his dynasty strategy video. Find more dynasty fantasy football strategy in our DSU section.