In America, one of the biggest controversies today revolves around a mere piece of machinery. While everyone has his or her own opinion as to the overall effect guns have on society, there has been little substantial research, except for the famous (infamous to some) study conducted by John Lott and David Mustard, who looked at FBI crime statistics across the U.S. from 1977 to 1992 to determine the effects of concealed carry laws.

A majority of states have adopted a policy that addresses the question of civilians carrying concealed firearms. The most common is the “Shall Issue” policy that requires local authorities to issue concealed carry permits to all who apply, provided they meet predefined, objective criteria. Usually this means that the applicant cannot be a felon and must have a clean mental health record. This system “removes all arbitrary bias and discretion, compelling the issuing authority to award the permit,” according to Buckeye Firearms Association (BFA), a gun advocacy group in Ohio.

Another concealed carry policy is know as “May Issue.” As implied, “the issuing authority ‘may' issue a permit if the citizen meets certain criteria,” ­according to BFA. This means that the issuance of the permit is almost completely at the discretion of the issuing authority, so the criteria may vary according to where the permit is requested. It's generally accepted that an applicant must have good reason for wanting to carry a concealed firearm, such as being a law officer or needing to walk through dark parking lots at night. Very few states have a “No Issue” policy where concealed carry simply isn't an option.

The benefits of allowing concealed carry can be seen through personal testimonies, but the real factor behind whether it should be allowed is how many lives are saved (or lost) as a result. According to the Lott and Mustard study, after several states adopted Shall Issue laws, there was a five percent decrease in rapes, an eight and a half percent decrease in murders, a seven percent decrease in aggravated assaults, and a three percent decrease in robberies. These aren't small numbers by any means. According to Lott, “If those states that did not permit concealed handguns in 1992 had permitted them back then, citizens might have been spared approximately 1,570 murders, 4,177 rapes, 60,000 aggravated assaults, and 12,000 robberies.”

The benefits aren't limited to individuals who actually carry firearms either. It makes sense that when a criminal knows that any potential victim may be armed, attacking someone becomes less appealing. “Unarmed citizens in effect ‘free ride' on their pistol-packing fellows,” writes Lott in “More Guns Equal Less Violent Crime.”

There are still some kinks to be worked out in the system, though. For example, research shows that criminals don't just give up crime after Shall Issue laws are passed. “Indeed, the downside of concealed-weapons laws is that while violent crime rates fall, property offenses like larceny … and auto theft rise,” writes Lott. This means that instead of committing violent crimes, criminals resort to crimes where they are less likely to confront their victims.

There have been instances where concealed carry laws result in accidental deaths or general misuse, but they are few and far between. In Florida, for instance, where over 300,000 concealed carry permits were granted over an eight-year period, only five violent crimes were committed using permitted handguns, none resulting in fatalities. According to some estimates, if all states were to adopt Shall Issue laws, at most another nine accidental deaths would be added to the 200 that occur annually involving handguns. “This is small indeed when compared to the at least 1,570 murders that would be avoided,” writes Lott.

With the subject of firearms so hotly debated, more research should be conducted, but what data exists seems to show that Shall Issue laws have a positive net effect on our society. While nonviolent crime increases, and there is a small increase in accidental deaths related to firearms, violent crime decreases greatly, leading to fewer deaths overall.