Mental models in DFS: Part 1, The Availability Heuristic

Post originally appeared in RotoGrinders

What are “mental models?”

The first time I came across the concept of using mental models in decision making was when listening to AngelList founder, Naval Ravikant, on “The Knowledge Project” podcast by Shane Parrish. The way he explained how any problem ranging from maths to philosophy to predictions, can be solved or avoided using a “lattice framework” of mental models has stuck with me ever since.

“A lousy way way to do…prediction” he says, “is X happened in the past, therefore X will happen in the future. What you want is principles. You want mental models.”

Why do we need mental models?

We all know that DFS, every day, comes with a lot of tough decisions. Many, like SaahilSud, use statistical models & analytical tools to get the upper hand. He’s even launched his own lineup builder, RotoQL, in which DK CEO Jason Robins invested in (a questionable move by many in the community). But for those of us who want to play more casually, yet still have a good chance of winning, what mental models can we use off the top of our head to ensure we make smart decisions every time? I feel like most casual players will enter a 1v1 draft or small contest thinking “Eden Hazard scored the last time I watched him play, he’s bound to score again.” Lousy.

I’ll be posting an article a week of the best mental models when it comes to making decisions in daily fantasy football. In some games, like DraftKings & FanDuel where huge GPPs mean smart decisions must be made at every turn, these mental models can be applied to existing mathematical frameworks to ensure higher chances of success. In others, like DRAFT or Dribble, they can be used as standalone to give confidence in making smart decisions when it comes to drafting.

What is the “availability heuristic?”

Let’s imagine that you’re walking down a busy street by a river on a Saturday. You see a busy restaurant filled with people. It’s brimming, you turn to your friend and say “I think I’ll invest in the riverside restaurant business, it seems booming!”

You’ve made two mistakes here. First, you’ve ignored the matrix of fact and second, you’ve failed to take into account the importance of base rates. What you’ve done fantastically well, is base your potential decision on the information immediately available to you. You’ve looked at one restaurant out of thousands in that area and decided that, because this one is full on this particular day, that the riverside restaurant business is worth investing in.

If you considered the matrix of facts you’d realise that of course the restaurant is busy on this particular Saturday. It’s a hot day, so anything by the river is attractive for foot-fall. It’s also a Saturday, so customers are more naturally looking for a place to eat. However, visit the same spot every day for the rest of the year & you’ll understand why it’s so important to consider all the facts before making assumptions. How’s business when it’s raining & cold?

I know I said that mental models are supposed to be quick frameworks to avoid spending ages on statistical analysis, but base rates are such a simple thing to figure out. A simple Google search shows you 60% of restaurants don’t make it past the first year & 80% go under in five. Now you’re thinking, is there anything about this particular restaurant that could pull it away from the base rate & into the 20% who survive past 5 years? That’s a better way to think.

The availability heuristic at work in DFS

Back to DFS, I experience this all the time. The most available information to me is the last game I watched, or the last set of highlights on YouTube. This is dangerous because we misjudge the frequency & magnitude of recent events. If I don’t know much about the Premier League & I see Michael Carrick score cracking goal, I think a great goal scorer. We also have limitations on memory, so it’s important to look at the matrix of facts when it comes to reviewing the fixtures & which teams are playing each other.

In “Thinking Fast and Slow”, Kahneman writes:

“People tend to assess the relative importance of issues by the ease with which they are retrieved from memory—and this is largely determined by the extent of coverage in the media.”

Articles & news reports about upcoming games are important to take into account into the matrix of fact, but don’t let them be your guiding hand. The writers themselves are often influenced by what they last saw. Don’t let your emotions get in the way either, especially in soccer, where passions can run high. Emotions in soccer shapes our intuitive perceptions and tricks us.

Beat the bias

So how can you use the availability heuristic to your advantage in DFS to gain the upper hand? Well, if the bias is inherent in all of us, it’s inherent in your opponents too. It’s therefore profitable to be contrarian, to look at players who haven’t necessarily done well in their last match but have a high average in their last five.