Recency Bias

There are good reasons why we focus so much on what a player just did.  The primary reason, of course, is that we have proof that it can happen and it might happen again.  Will they keep it rolling?  What sort of momentum can they build?

Surely if they just did it, then it has a great chance of happening again.  They've proved that they have this skill.  Right?

We do this week to week in football but also season to season.  In baseball, basketball, and hockey it feels like almost a day to day thought process.  Each of these have their own merits but they have very different impacts on your fantasy roster.

And, listen, I'm here to tell you that what happened last week is about the worst thing to use as a basis for your weekly waiver wire picks in fantasy football.  Think about it logically and you may find yourself giving your own head the facepalm.

Why?  Let me count the ways:

• Team Matchup - Perhaps there were team reasons why a player got certain statistics last week.  The game plan could have been specifically designed based on the strength or weakness of the opponent and that led to the accrual of fantasy points for the player in question.
• Unit Matchup - Was this running back playing against a bad run-stopping defensive line?  Or, did the defensive line fail to generate a pass rush to interrupt the rhythm of a particular waiver wire quarterback option?  Last week's unit matchup might be the reason for those great stats.
• Individual Matchup - Did the wide receiver exploit a great matchup against a poor corner back?  Did this tight end find themselves matched up against a beatable linebacker all day?  This happens all the time.  Every week, in fact.  There is always a player who goes off based on a favorable individual matchup.
• It's Just One Week - Above all of these matchup considerations, remember that last week's stats were just one week.  If you are six weeks into the season and the player was great in week #6 but lousy in weeks one through five, ask yourself why.  Why did the player go off?  Maybe it's just one of those fluky things.  Maybe they were an injury replacement.  Maybe they had a great matchup.  Who knows?  It's important to realize that it is in fact only one week.

In "The Program" we instruct fantasy players not to grab a player early in their draft based on one good season.  Not unless you have many "green flags" that point to a strong outcome.  It is the same with these week to week (or even day to day in other sports) decisions about waiver wire adds and free agent pickups.  Be shrewd in your evaluation of what they are likely to contribute to your squad and do your best to avoid recency bias.