Abstract from study at: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=161637 “Our results are surprising and dramatic. While arrest or conviction rates and the death penalty reduce normal murder rates, our results find that the only policy factor to influence multiple victim public shootings is the passage of concealed handgun laws.” See also: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=272929