The mistake almost everyone makes in fantasy football

Super Bowl LI quarterbacks Tom Brady and Matt Ryan could both have been on your team in 2018, but starting the wrong one regularly over the other was the wrong decision. Which would you have made? EPA/LARRY W. SMITH

Picture the following scenario from last football season: You draft Tom Brady, planning for him to be your starting QB for the season. In a late round, you pick up Matt Ryan as a bye week and injury fill-in. As the season goes on, you stick with Brady as your starting QB even though Ryan keeps putting up more fantasy points. Each week, you review ranking after ranking until you find one that has Brady over Ryan and then slot Brady into your lineup again, sinking your playoff hopes. This sort of behavior is very common in fantasy football. It seems totally irrational, so why do we do it?

This article is the second in a three-part series on how decision analysis can improve your fantasy skills and help you navigate decisions in all aspects of your life. The first article explains how and why you should focus on your decision-making process. This article explains how you can improve your decision-making process by recognizing and resisting confirmation bias.

What Is confirmation bias?

Confirmation bias occurs when we prefer information that confirms our existing opinions. Rather than objectively viewing all the information before forming a belief, we often form a belief first and then seek out confirming information while ignoring or discrediting contradictory information. Instead of seeking out the whole truth, we cherry-pick information to support our views. Like the concept of outcome bias described in the first article, confirmation bias is a cognitive bias, or hardwired misjudgment that leads to irrational thinking. Psychologists have consistently observed the effects of confirmation bias in multiple domains, from politics to medicine. Confirmation bias leads us to be closed-minded and blindly stick to beliefs regardless of the available information. Although we generally think it is a good thing to have a strong opinion and to stick to it, for effective decision-making, we must update our beliefs in light of new information.

How this applies in fantasy football

Confirmation bias can affect all fantasy football decisions, from drafting to start/sit calls to trades. In all of these cases, we often form a belief without having considered all sides, seek only confirming evidence, and are unlikely to change our minds. In the Brady-Ryan example above, confirmation bias causes one to stick to beliefs even when it is against their best interest. You drafted Brady to be the starter and Ryan to be the backup, and you are predisposed to want to stick with that belief. Perhaps you are even a Patriots fan, and want to believe that Brady is a better quarterback than his Super Bowl LI opponent. That leads you to cherry-pick facts rather than trying to determine the whole truth. You will see Ryan ranked above Brady in all the rankings, and see Brady in Matthew Berry's "hate" list, but you'll do mental gymnastics to convince yourself why the critics are wrong or just ignore this contradictory information altogether. You'll keep searching until you find any expert who agrees with you or some stat that supports your view. You might change your belief at some point, but it would take something extreme like Ryan putting up massive numbers for six consecutive weeks or Brady getting injured. In general, you're likely to stick with your belief because you will only seek out confirming evidence.

Matthew Berry's 100 facts article clearly illustrates the role of confirmation bias. He explains right from the start that for each player, there is a tremendous amount of stats and other information available, both positive and negative. Fantasy owners tend to pick the data they want to prove their point and ignore the rest. As he shows with the Player A vs. Player B example, you can cherry-pick facts to make compelling arguments both for and against a player.

Confirmation bias plays out not only in the way we research, but in how we seek advice from friends. Many fantasy owners "shop around" until they get someone to say what they want. For example, you get excited about a trade you put together and text a bunch of friends to see what they think. In theory, you're asking for their objective opinion to help you decide whether to go through with the trade, but in reality, you want someone to agree with you. If the first few people don't give you the opinion you want, you are likely to ignore or discredit them and keep looking until you find someone who agrees with you.

How to combat confirmation bias

So, what can we do about this? The good news is that you can use a two-part strategy to help you overcome this bias and make better fantasy decisions.

First, try your hardest to have an open mind and seek out the whole truth before forming an opinion. For any fantasy decision, consider various sources of information (including a wide range of stats and different expert rankings or other articles) and make a simple pro-con list. The process of actually putting the pieces of information in the two buckets will force you to at least consider both sides and provide a more comprehensive understanding of the decision. For a more rigorous analysis, you can think of the importance of each piece of information relative to the others, because not all information is created equal. For example, for a running back, the fact that he had 30 touches a game for four weeks straight is a more compelling piece of data than a slight injury to one of his offensive linemen.

Second, once you've formed a belief, be willing to change your mind and look for counterevidence. Ask yourself, "What information would change my mind?", and then look to see if such information exists. For example, when you fall in love in with your defense after four stellar weeks to start the season, you should test your belief by looking for information that might change your mind -- such as that the opposing offenses for the first four weeks are all at the bottom of the league in performance, and your defense is facing two high-powered offenses in Weeks 5 and 6. You should update your belief and maybe at least pick up an additional defense in the short term.

How this applies in life

Confirmation bias affects decision-making in many contexts outside of fantasy football. In our personal lives, for example, we often act as if we're consulting friends for advice when we really just want our friends to tell us what we want to hear. Confirmation bias is also clearly visible in our political beliefs and media consumption. We have a strong tendency to only consume media and information that confirms our existing views, whether it is through the news channels we watch, the sites we visit, the people we follow on social media, or the books we read. For example, in "You Are Not So Smart," David McRaney describes a study of Amazon purchases during the 2008 presidential campaign that found people who already supported Barack Obama bought books that portrayed him in a positive way, and people who already disliked him bought books that portrayed him in a negative way. Confirmation bias can lead to polarization, as people are only exposed to information and opinions that support their own views. To have a more objective understanding and see the shades of gray, it is important to engage -- with an open mind -- with all sides of an issue and to update our beliefs accordingly.


You can make better decisions this fantasy season by being aware of confirmation bias and using a two-part strategy to overcome it. First, try to have an open mind and seek out the whole truth before forming an opinion. Second, once you've formed a belief, be willing to change your mind and look for information to update your beliefs. Overcoming confirmation bias will increase your chances for fantasy success and also help you be more informed, objective, and rational in all parts of your life.

This article is written by The Alliance for Decision Education (formerly How I Decide Foundation), an educational nonprofit dedicated to the belief that better decisions lead to better lives and a better society.