I'm going to copy/paste something I posted in another thread on this post:
It's my opinion, maybe only my opinion, that firearms are primarily a deterrent. That is if one pulls the trigger the firearm has failed at its primary purpose. Perhaps it has failed even if it has to be brandished. There's a problem measuring a firearm's effectiveness as a deterrent...it's almost impossible to measure because it isn't reported.. It doesn't show up in police reports etc. "I didn't rob that guy because I think he might have been packing."
The numbers for K&G do seem inflated. If they had come up with some way to measure "deterred via brandishing or suspecting potential victim was armed" then I would be more willing to accept the number as stated.
The two important parts here are:
that the reports are cited and available for analysis and debate. That is a pattern that I almost always see for pro-gun arguments and almost never see for anti-gun arguments.
that the number of crimes prevented by private firearms ownership far outweighs the number of crimes perpetrated due to private firearm ownership. The delta is large enough according to almost every attempt at rigorous analysis of the situation that I'm fine summarizing that as "lives saved large than lives taken".