A trend in policing and in business, evidence-based decision making is a process whereby research is used to help people construct the best policies, best organizations and the best practices to solve the actual problem one has rather than making reactive decisions to the problem one thinks one has.
When it comes to gun issues, time and time again I see people who purport to be liberals rushing to legislate and restrict gun ownership without trying to find and assess what is going on. A big one is trying to oppose concealed carry licensing, when in fact those who have licenses are the least likely to commit gun crimes.
http://www.lesjones.com/posts/004329.shtml
Maybe someday we can make evidence-based decision making a part of politics and media as well.