I don't have the numbers in front of me (might be on GunFacts), but a study done a few years ago in Texas concluded that people licensed to carry concealed handguns are MORE LAW ABIDING than THE POLICE and that a significantly higher number of police officers are charged with crimes than CCWers.

Another study shows that police officers are something like 5 times more likely to "shoot the wrong person" than a citizen carrying a concealed weapon (to be fair this is often because the police arrive on the scene after action has started whereas the citizen is there from the very beginning).