Action bias in pregnancy, soccer, and foreign relations

So, earlier this week, I listened to a really entertaining new podcast from Slate and WBUR on health called the checkup.  This edition focused on myths of pregnancy and childbirth.  What I found most fascinating is that bedrest during pregnancy is still widely prescribed despite absolutely no evidence that it does anything to improve the conditions it is supposedly treating.   Pretty amazing, huh?  So, why in the world do doctors regularly prescibe a treatment that in all likelihood does more harm than good?  (Not suprisingly being stuck in bed can easily lead to depression).  Short answer, is that there is no known effective treatment for symptoms of pre-term labor.  And here’s the thing– if you are doctor or a pregnant woman you want to do something.  It’s human natue to want to do something (anything!) when faced with a difficult situation.  Its just so hard to sit back and do nothing even if science and common sense (i.e., I’ll drive 10 minutes out of my way to avoid a traffic jam I know will take 5 minutes) dictate that this is the best approach.

Same day I listened to this, for some reason I came across a 5-year old Shankar Vedantam piece on how this “action bias” on authorizing the Iraq War where he also pointed out the fun finding on how detrimental it is to soccer goalkeepers facing a penalty kick:

Economist Ofer Azar recently came up with a novel way to study the insidious nature of the action bias. He examined whether soccer goalies were more likely to stop penalty kicks when they dived to the left, dived to the right or stayed in the center of the goal. In a study of 286 penalty kicks faced by elite Israeli goalkeepers, Azar found that goalies had the best chance of stopping a kick when they remained in the center — partly because when they dived to one side, they left themselves with no chance of stopping a kick aimed at the other side or a kick aimed dead center. And even when they correctly guessed the direction of the kick, they still had only a 1-in-4 chance of stopping a goal.

Despite the clarity of the evidence, Azar found that goalies dived to one side or the other 93 percent of the time.

Lesson?  Next time you think you just have to do something, you probably really shouldn’t.

About Steve Greene
Professor of Political Science at NC State

One Response to Action bias in pregnancy, soccer, and foreign relations

  1. itchy says:

    The concept of action bias sounds very plausible, and there are real examples in so many situations.

    But this study seems like game theory, where the history of actions of one player affect the actions of the other — and Azar isn’t taking that into consideration.

    The study says that goalies stopped 33% of shots when they stayed in the center and 25% when they dove to a side. That’s a significant, but not huge, difference.

    But I contend that if a goalie only ever stays in the center, most pro players could score nearly every time. It’s when the goalie occasionally jumps — and yes, 93 percent is far more than occasional and might be too frequent — that the shooter can’t be assured that he can just hit either corner. He has to juke and try to trick the goalie, etc.

    It’s possible — I’d say likely — the the total scoring percentage is lower with a goalie who sometimes dives vs. a goalie who only stays in the center. But there are no goalies who only stay in the center, so Azar didn’t have the control group.

    This reminds me of a pitcher mixing in a changeup with his fastballs. His changeup might get hit more frequently than the fastball, but his fastballs would be hit *much* more frequently if he didn’t have the changeup at all.

    I do agree, though, that the goalkeeper probably isn’t thinking all this; he really is thinking, “I have to make something happen.”

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