*  This story shows how things that seem bad may be good if they prevent something worse. Ed McCaffrey, a Stanford-educated former wide receiver, uses this argument to justify letting all four of his sons play football: “These guys have energy. And, so, if they’re not playing football, they’re skateboarding, they’re climbing trees, they’re playing tag in the backyard, they’re doing paintball. I mean, they’re not going to sit there and do nothing. And, so, the way I look at it is, hey, at least there’s rules within the sport of football. . . . My kids have been to the emergency room for falling off decks, getting in bike crashes, skateboarding, falling out of trees. I mean, you name it . . . Yea, it’s a violent collision sport. But, also, my guys just have the personality, where, at least they’re not squirrel-jumping off mountains and doing crazy stuff like that. So, it’s organized aggression, I guess.” McCaffrey’s argument, made in an interview on The Herd with Colin Cowherd, is one I had never heard before. After reading the Dahl/DellaVigna paper, I take the argument seriously. An advantage of huge real-world datasets, rather than laboratory data, is that they can pick up these kinds of effects.