The success of concealed-carry laws

In light of the mass shooting at Sandy Hook elementary school in Connecticut, many have been discussing a particular solution to the problem of these kinds of shootings. It's the idea that if we had many more people carry concealed guns, we would be safer for two reasons:

• Some criminals would be deterred since they could face being stopped, captured, and even shot.
• Criminals intent on their crimes would be interrupted by being shot.

However, opponents counter with these disadvantages:

• With more people armed, there would be more gun altercations in the heat of emotions.
• In a tense, fast-moving situation, the vast majority of gun carriers don't have the skills to react properly. 
• They may make the situation worse with uncontrolled firing and false bravado.

I researched these issues, not exhaustively, but looking for clear evidence for or against concealed carry. What I found was that concealed carry doesn't cause excessive problems. The data is equivocal. In general, crime has been decreasing, whether new concealed-carry laws are enacted or not. There's no clear trend that concealed-carry deters crime (link pp.80-83), but it definitely doesn't seem to increase it.

In most states, a permit to carry a concealed weapon isn't simple to obtain. For example, Colorado has this long list of requirements: fingerprint check, background check, no restraining orders, no chronic alcohol or drug abuse, certificate of firearms training. That sounds like a list that would weed out most of those who shouldn't be carrying around guns.

Even organizations that are against concealed-carry provide data showing that it is relatively rare that people with concealed-carry permits commit crimes. From May 2007 to December 2012, 499 people have been killed by assailants who had concealed carry permits. Compare this to the total number of homicides over the same period, which I estimate to be 83,500 (extrapolating from FBI statistics). That is roughly 0.6% homicides from a population (roughly 8 million) that is 2.6% of the US population.

This doesn't mean that concealed-carry laws are without problems. Florida has accelerated the permitting process and also passed "Stand-your-ground" laws that may be contributing to unwarranted, indefensible shootings. That is why I support more stringent requirements like those of Colorado.

Are there any benefits from concealed weapons? Yes. On at least a few occasions, people with concealed weapons have ended shooting rampages. This is in addition to the many times when those carrying have defended themselves or prevented attacks.

Review of advantages/disadvantages of concealed-carry:

• Some criminals would be deterred. (Probably true, but marginal)
• Criminals intent on crime would be interrupted by being shot. (Rarely)
• With more people armed, there would be more gun altercations in the heat of emotions. (False)
• In a tense, fast-moving situation, the vast majority of gun carriers don't have the skills to react properly. (True)
• They may make the situation worse with uncontrolled firing and false bravado. (False so far)

Other interesting links:

• Concealed carry and crime statistics in N. Carolina.
• Study of attacks on police officers--mostly illegal firearms.
• Stories of killings - people who shouldn't have access to guns but did.
• John Lott's controversial study of concealed-carry.
• Statistics on crime by permit holders - not huge numbers.
• Concealed-carry would not have stopped the mass shooting at Aurora.
• Mass shootings and high capacity rounds.