Tuesday, April 17, 2007

Gun Control: Get the Right Numbers

Over at Mike the Mad Biologist's blog, the discussion has begun about gun control. Unfortunately, too often these discussions involve horrible use of logic and statistics, and this one is no exception.

Let's start with something Mike gets right that most people don't:

"... had the Virginia Tech students been armed, fewer students would have died...Of course, at that moment, you would probably be safer...What is missing ... is any serious thought about all of the ramifications."

Many gun control supporters make the mistake of denying the obvious here, probably because they subconsciously think that admitting the obvious (a group of armed people are going to die at a lesser rate than a group of unarmed ones if attacked by a lone gunman) concedes some important point. It doesn't, because it is the wrong question. What we care about is the overall death rate under this or that law, not what happens in one particular instance.

from other posters:

"I like to look at the numbers: the stats I've seen say a handgun in the home is 20-40 times more likely to shoot someone in a suicide, crime of passion, accident, etc. than it is to be used to defend a home."

The referenced study was conducted by doctors Arthur L. Kellermann and Donald T. Reay ("Protection or Peril?: An Analysis of Firearm-Related Deaths in the Home," New England Journal of Medicine, 1986). The figure was 43, and it referred to people killed by the gun in their home, or an intruder being killed in self-defense. Scaring off or injuring an intrudor didn't count, and no mention is usually made of the fact that most of the deaths were suicides. There is a more detailed examination here. Suffice it to say, the study does not address the relevant issues.

"Everyone should have a small nuclear device strapped to their back. This will be rigged to go off at the first sign of violence (Being shot, stabbed, punched, etc). Everything within a 500 meter radius will be vapourised. Just imagine how polite society would become. And how little crime there would be!"

Amusing, but off point. Nuke's kill indiscriminately, whereas the gun can be controlled as to who is fired at, albeit imperfectly. Also, the rigging of the nuke removes the valuable judgement a gun wielder can exercise. After all, no one is suggesting gun owners should shoot automatically at the first sign of violence!

"The evidence seems to suggest that limiting gun ownership, espcially handguns, does stop people being killed by them."

Of course it does, but that borders on tautology, and misses the point of the exercise. Consider suicide as an illustration, which is about half of gun deaths. If we successfully banned guns tomorrow, and yet found that our suicide rate was not reduced, would that not be a hollow victory? Hey, we reduced gun suicide 100%, woohoo! Not. Our purpose is to reduce death, not just death by gun.

Some people who intend to kill themselves are going to find other ways to do it. Many already do. Ditto for murder victims. The number that died by gun recently that would have died even in the absence of guns is not zero, and their deaths are no less tragic.

Also, talk of people being killed by guns ignores important context. The death of a 12 year old girl who was shot by her friend after finding Dad's gun concerns me far more than the death of a thrice-convicted felon shot by a police officer in self-defense. Homicides worry me far more than suicides. Yet these broad brush statistics take none of this into account, and as a result, exagerrate the perceived risk. So do not speak of "gun deaths". That's meaningless.

"What this person is suggesting is that every confrontation on a college campus, or in an office building, or a public school, or a crowded shopping mall, or in a packed bar, or on a busy city street, should have a vastly increased probability of ending in a shootout."

This is the flip side of the first point I made here. Gun ownership advocates too often dismiss the increased probability of conflict inherent in having everyone armed. What happens to the total conflict is a different question, and ignoring the fact that many scenarios exist where the presence of guns increases the risk, adds no credibility to one's opinion of the bigger questions.

Notice also the fallacy of talking about "gun" violence cropping up again in the above note. Of course the probability of a "shootout" is higher with guns than without. The more relevant question is what the probability of violence, death and injury is, regardless of the source.

Also inherent in the quote above is the false assumption that the pro-gun guys advocate everyone having a gun. Far more prevalent is the notion that it would be beneficial for more people to have guns, but only a nonrandom subset of the populace doing so, steering away from those prone to crime, violence, etc.

"if someone has a gun pointed at you, and you reach for a gun, you will very likely get shot."

This is one of many red herring scenarios that people pose as representative. Obviously if the person is right in front of you with a gun pointed at you, you are in grave danger, carrying a gun or not. However, gun defense also includes scenarios where the attacker is not armed, or less armed, or further away, and focusing on this extreme rare scenario misses the bulk of the picture.

The bottom line is this: to make good decisions on issues like gun control, we need to have good complete data and ask the appropriate questions. We are trying to reduce deaths, not "gun deaths", crime, not "gun crime". Let's be more open about what gun deaths are: roughly 50% suicides, and including shootings all but the most granola-carrier doesn't mind so much, like police shooting career criminals in self-defense. It's the innocent we are trying to protect, so let's concentrate on that.

No comments: