Sunday, November 22, 2015

Criminologist Gary Kleck on Guns, Crime, and Their Study | Ari Armstrong

Criminologist Gary Kleck on Guns, Crime, and Their Study | Ari Armstrong

The Cost of Good Survey Results
Armstrong: You did such a study at one point. Would anything tempt you to conduct another such study at some point in the future? What sort of work-hours are we talking about here?

Kleck: Yes, but it’s a matter of somebody has to pay for it. I imagine these days telephone surveys similar to my previous one would probably cost you on the order of $50 for each completed reply.
Gun Ownership and Violence

Armstrong: Various studies have claimed to show that buying or owning a firearm makes one more prone to being involved with violence. Usually these are in medical journals. What do you think of these studies?

Kleck: The authors didn’t really seem very interested in falsifying their hypothesis. Good researchers make a serious effort to show that their initial hypothesis is wrong, and then, when they fail repeatedly, it’s a strong indication that we ought to tentatively accept the hypothesis or at least not reject it.

In this case, that would mean you would ask a lot of questions about confounding factors, other things that would affect whether or not people got involved in violence besides having a gun in their household, that might also be correlated with gun ownership. You might confuse the effect of these confounding variables with the effect of having a gun in your home.

Since these studies really don’t make any serious effort to control for those factors, you really don’t know much about them.

As far as we can tell, the only reason why people who end up getting murdered were more likely to have a gun in the household is because they live in more dangerous circumstances, and they anticipated the need to have a gun for self-protection. So, if you live in a dangerous neighborhood, or you know dangerous people, or you go into dangerous places, then you are more likely on the one hand to get murdered, but of course you’re also more likely to acquire a gun somewhere along the line for self-protection. So it’s a classic case of a spurious association.

None of these studies has made any serious effort to control for those sorts of factors, things like belonging to a street gang. You’re way more likely to own a gun, and you’re way more likely to get murdered. If you don’t control for whether a person belongs to a street gang, you’re not really going to get a serious estimate of the effect of having a gun.

Probably the best of a bad lot was the famous Arthur Kellermann study from 1993 in the New England Journal of Medicine. All the rest are even worse, but at least he controlled for a few possible confounding factors. But he withheld one crucial piece of information from his readers. He knew that virtually none of the people who had been murdered while having a gun in their home had actually been killed with the gun that belonged to someone in the home. They were almost always killed by someone from outside the home, presumably using their own gun, brought in from outside the home. So whether the victims had a gun of their own in the house had absolutely nothing to do with the event. And Kellermann withheld that information, and a lot of people noticed the problem right away. There were even letters to the editor of the journal asking “what gives,” and he responded with a very evasive answer in his reply to the letters.

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