action bias

July 2026

why are footballers not maximising their ev?

read a guardian piece on statistics behind penalty kicks, largely based on almeida 2016.

we can see a lot of action bias:

keepers dive more than they should, and pen takers shoot low more than they should - both would be probabilistically more likely to score if they dived less/aimed higher. however due to their utility functions, which likely have a bit of selfpreservation and wanting to look good, they choose the lower risk option, diving so it seems theyre doing something, or having a pen saved rather than off target.

sort of links back to my post about behavioural economics - theres more to maximising utility for someone in that situation than just purely the % of scoring.

as i am writing this i have also thought of potential selection bias in the data - players that aim higher are more confident -> better -> more likely to score regardless. so potentially this data is actually very misleading, but thats a thought for another day.