His basic argument is that the increased cost to would-be perpetrators (i.e., the risk of being caught or shot) convinces them to refrain from murder, rape, robbery, and assault. Guns used defensively, or even the prospect of guns being used defensively by potential victims, is enough to scare some criminals into pursuing less violent careers.
Hot Chocolate Consumption and the Crime Rate
But people with permits for concealed guns are presently those whose work puts them at increased risk or else people who are prudent, but fearful. What would happen if concealed weapons became the norm? Just because a certain relationship (more guns, less crime) is linear and negative over some range of the independent variable doesn't mean it will remain so over a much bigger range.
And even if this negative linear relationship were to hold up with many more people carrying guns, do we really want to decrease the crime rate in this way? There is a considerable psychic cost to being a citizen in a nation of armed people warily navigating their way through their crime-free lives. Some version of the somber anxiety that one experiences going through airport luggage scanners would extend throughout one's whole life.
There remain also the usual problems associated with all correlations and regressions. Is the association, even if real enough over a limited range, a causal one or is it coincidental? Or might there be a factor, not yet identified, leading both to more concealed gun laws and lower crime rates? After all, more consumption of hot chocolate is also associated with less crime and both are brought about by cold weather.
The bottom line is that our understanding of crime rate fluctuations is still very murky. Why the sudden precipitous drop in the murder rate in New York City, for example — the economy, demographics, enforcement? Cultural factors, while hard to quantify, certainly play an important role.
Some countries like Japan have few guns and little violent crime, whereas others have few guns and a lot of crime. Similar variation holds in countries with a lot of guns (or should I say a Lott of guns). In Switzerland and Israel a very high percentage of citizens have guns and the crime rate is low, whereas in this country many people have guns and the crime rate is high (although down considerably from its peak).
Although the iconoclasm, statistical presentation, and simplicity of the book's sales pitch are appealing, I simply don't buy it.
Professor of mathematics at Temple University, John Allen Paulos is the author of several best-selling books, including Innumeracy and A Mathematician Reads the Newspaper. His Who’s Counting? column on ABCNEWS.com appears on the first day of every month.