Metric of the week: Card and Dahl on Upset Losses and Family Violence

Posted on 1 April 2011 by

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The metric of the week is one that refers to a phenomenon that cops have sensed forever: family violence – specifically male to female violence – rises when a team that’s been heavily favored to win an NFL football game loses.

The authors, David Card and Gordon B Dahl, state that two other recent studies demonstrate this clearly – Gantz, Bradley and Wang wrote in 2006 on increased family violence on football game days, and Rees and Schnepel wrote in 2009 on the link between college football, assault, vandalism and alcohol-related crimes.

Card and Dahl say that their study looks deeper at the problem created by a high expectation of a win followed by a surprise loss, and how that affects family violence rates. They say: more.

The paper would be interesting if only to look at how they grappled with the issues at hand, and to gawk at the methodology. But there’s much more than that. The authors don’t seem to be saying that it’s only pro-football or even only football at the heart of the problem, but that they studied football because there’s lots of hometown loyalty, the betting markets are mature and easy to understand, and statistics (so they can identify the games which would be of interest) are very easy to come by.

They looked at family violence data from more than 750 agencies and Sunday NFL games played by six teams over a 12-year period. The research was supported by a grant from the National Institute of Child Health and Human Development, and the article, Family Violence and Football: The Effect of Unexpected Emotional Cues on Violent Behavior was published in in The Quarterly Journal of Economics.

Card and Dahl found that while an upset win – that is, the home team being favored to lose and then winning – did not have a significant effect on domestic violence rates. But they found that

“‘…upset losses’ by the home team (losses when the team was predicted to win by four points or more) lead to a roughly 10% increase in the number of police reports of at-home male-on-female intimate partner violence … We also find that upset losses in more salient games (those involving a traditional rival, or when the team is still in playoff contention) have a bigger effect on the rate of violence.

There follows a bunch of very cool and to me utterly unfathomable modeling of different behaviors which I won’t pretend to understand. I’m not a statistician or math wonk, I’m just a metrics fanboy.

So the metric of the week is absolutely the rule of thumb that, if the home team loses a game it was supposed to have won, we can expect a spike in domestic violence.