Richard Florida wondered what factors he could draw statistical correlation with for death by firearms and concludes:
>While the causes of individual acts of mass violence always differ, our analysis shows fatal gun violence is less likely to occur in richer states with more post-industrial knowledge economies, higher levels of college graduates, and tighter gun laws. Factors like drug use, stress levels, and mental illness are much less significant than might be assumed.

Very interesting analysis — by no means is it proof of anything, rather just a correlation between two data sets. Still, it is apparent that change is needed — whether or not you believe this data.