[Brian Pfleuger]

Of course, to truly know if something like CCW has any effect on crime it would have to be introduced in significant numbers very quickly, to an area that previously had no legal carry method. Otherwise, there is simply no way of isolating the effect of CCW. Things like entire societies are simply too complicated with far too many variables to be able to identify solid causal relationships over an extended period of time.

For example, New Orleans has CCW but we have NO WAY of knowing if the crime rate would be higher or lower or indifferent without it. DC could actually be a good testing ground. If they are forced to allow concealed carry in the near future and they issue thousands of permits in a short time then we may be able to identify a positive correlation.

You simply cannot take a snippet of time from a complex equation and identify the effects of any variable you choose.

XYZ city has CCW and low crime. Is there a correlation? Maybe it's because it's a Bible belt city and they have more devout Christians. Maybe they've got a judicial system that's tough on crime. Maybe it's low unemployment. Maybe it's because they're not on a major highway that serves as a drug route. Maybe it's a combination of all those things and more.
There is simply NO WAY to tell.