Vivek Haldar

To jump or not to jump?

In professional-league football, the probability that a penalty kicker will shoot towards the middle of the goal is roughly 29%. On the other hand, the probability that the goalkeeper will stay at the center of the goal, and not jump left or right, is only 6%.

This is a scenario where experienced professionals have huge financial incentives to make the correct decision. The goalkeeper cannot feign ignorance, because he clearly must have faced a large number of penalty kicks during his career. Then what explains this behavior?

Norm theory posits that regret from a bad outcome is much worse when the outcome follows an unusual action – whether or not the action was the cause of the outcome. In a given scenario, if the norm is to do nothing, and you end up in a mess because you did something, it feels much worse than if you ended up in a mess doing nothing. Conversely, like in the case of goalkeepers, if the norm is to move, and your opponent scores a goal because you stood still, that looks much worse than if you jumped.

Often we end up following the normal course of action even if it is not optimal. When something goes wrong, our first instinct is to change something. When things are going well, on the other hand, the tendency is to not change. Just because these are the normal actions, we should question ourselves every time we catch ourselves doing it.

How do you know if your behavior in a situation is optimal, and not just the psychological reflex predicted by norm theory? You can tell what the norm is by simply observing a situation for some time. To both players and followers of football, it is obvious after a while that, for goalkeepers, jumping is much more common than standing still. But to really know what course is “optimal”, you need hard data. You need to know that kickers will shoot center 29% of the time.

This post is based on the following paper:
Bar Eli, Michael, Azar, Ofer H., Ritov, Ilana, Keidar-Levin, Yael and Schein, Galit, Action Bias Among Elite Soccer Goalkeepers: The Case of Penalty Kicks. Journal of Economic Psychology, Vol. 28, No. 5, 2007. Full paper (PDF)