Wednesday, April 18, 2007

Guns and crime in Virginia

In the midst of all this talk about the Virginia school shootings, a lot of commentators have seized the opportunity to talk about gun control, either for or against. Gun control advocates are saying that this is obvious proof that guns are too prevalent. Anti gun control types are just as certain that this proves we need MORE guns, because some cool headed Rambo might have blown away the perpetrator if only guns had been allowed on campus.

This seems like as good a time as any to dredge up the term paper that I did with Chip Killmar for Data Mining last year. I'm at least somewhat familiar with the politics of gun control, although it's one of the positions that I doggedly refuse to take a firm position on it.

Many people cite statistics that claim to show that states which allow concealed weapons have less violent crime than states that do not. In fact, there are a lot more factors which contribute to violent crime rates. The most often cited expert in favor of concealed-carry laws is John Lott, who has written several books under titles like More Guns, Less Crime. However, Lott's methods are extremely suspect and generally not very convincing, for reasons we go into in the paper.

Density of population is the leading contributor to overall violence levels. States with large, crowded cities tend to have much higher populations than those with mostly small, rural areas. Not (necessarily) coincidentally, small rural areas are much more likely to have a strong NRA presence, and those are the states that tend to pass Shall-Issue Right-To-Carry laws, giving nearly all citizens easy access to permits that allow them to pack a concealed weapon, barring criminal records and other extreme circumstances.

As a result, people who claim that gun-friendly laws are successful often point to raw crime statistics, correctly stating that states with RTC laws have less gun violence on average, but failing to note the other significant factors such as density.

Also, throughout the 1990's, crime decreased nationwide. Since previous studies of the effectiveness of RTC laws mostly occurred during the 90's, they showed crime decreasing AFTER the passage of these laws, and invoked the common "post hoc ergo propter hoc" fallacy to say that the laws themselves were the cause of reduced crime. Yet crime also went down in areas that didn't institute such laws, often (though not always) even more than in pro-gun states.

Currently 37 of the 50 states have shall-issue laws, with more than half having been instituted after 1987, when Florida become a leader in doing so. Our project compared cities across the US and factored out the population size of each city. Anecdotally, some of the highest crime rates in the country are found in cities like Miami, Dallas, and San Antonio: all of which are very large cities which happen to exist in states (Florida and Texas) with long-standing RTC laws. By contrast, New York City, which is frequently associated with high crime, actually has some of the lowest violent crime of any major city, and New York State remains one of the states that has not issued any law favoring concealed weapons.

Our final results were inconclusive, because the error bars are very high and it's difficult to do a reliable city-by-city comparison without knowing more about the contributing factors. However, the data tentatively indicates that there is indeed a somewhat significant increase (mostly around 10-20%) of murder and rape in the few years following the institution of a RTC law, over a city of similar size which did not issue that law over the next several years.

By the way, Virginia has a shall-issue law. They have since 1995. In many ways the state of Virginia is a shining example of what kind of laws that the NRA would like to see instituted nationwide. I've read that even in RTC states, very few people actually carry concealed weapons. So often the theory is floated that in a state with an RTC law, crime is deterred because criminals are SCARED that they'll get shot. Clearly this was not the case yesterday, nor is it surprising that a lunatic going on a shooting rampage is unlikely to consider the finer points of state laws.

Am I in favor of banning guns? No. Even if it were conclusively proved that a certain level of crime were caused by guns, I think the case can be made that constitutional principles override an outright ban. After all, even freedom of speech and the press certainly causes harm, but we believe that the principles of free speech and press are often more important than a little additional safety. On the other hand, I don't see any serious problem with making people jump through more hoops than they currently do before they can use a gun, just as we make people get driver's licenses and it's possible to revoke those licenses.

Could a pistol-packing student have prevented the massacre in Virginia? Nothing's impossible, but consider that this was an extremely rare event. In order to create a happier ending, a heroic student would have needed to be present, who happened to be packing that day, had the presence of mind to shoot the guy, didn't get himself shot first, and didn't make the situation worse by shooting innocent bystanders in the process.

Furthermore, suppose that there are TWO heroic students, who each hear the shot and whip out their concealed weapons. They don't know who's firing, but they see each other holding a loaded firearm. How do we know they don't shoot each other? When the police arrive, how do they know that they are not accomplices to the crime, and gun them down? Now multiply this risk by the number of days that numerous students are walking around campus with loaded guns, and a particularly crazy guy is NOT walking around campus (i.e., almost every day, in every university). Are we really saying that all these extra guns create no additional opportunities for more incidents?

I don't know the answer to that, of course, but neither does the NRA. That's why I'm mostly for people's right to own as many personal firearms as they wish in their houses, preferably with some kind of mandatory training; but I'm still extremely dubious about these concealed weapon laws.

1 comment:

  1. You are wise great Kazim. Interesting information particularly about density of population.