Every Mass Shooting in the US Since the 1950s Except Two Occurred in Gun Free Zones

Every Mass Shooting in the US Since the 1950s Except Two Occurred in Gun Free Zones ⋆ Conservative Firing Line
A professor from Purdue researched mass shootings from the 1950s on and discovered that only two of them occurred where guns are legal to be carried. 
This really blows apart liberal arguments that more guns means more mass shootings. Between 2004 and 2012, gun ownership increased by 61%. 
But since 2008, violent crimes decreased by 12.9%. Eric Dietz, Ph.D., the former director of Homeland Security for the state of Indiana and a 22-year Army veteran, and now a professor at Purdue University, set out to find out how armed citizens could prevent deaths.

In order to examine the results, he chose to study the most common gun free zone in America, and also the place most mass shootings take place, (Outside of Chicago) public schools. 
Dietz outlined 4 scenarios and using statistical math, developed a model whereby he could estimate the results. 
He noted that since schools are gun free, they have to rely on the police, who on average take 10 – 12 minutes to respond to a live shooting. 
Given the fact that a mass shooter can kill a person every twenty seconds, the delay can costs a lot of lives.

Here are the four scenarios Dietz used in his study:

• Scenario 1: No access to control or security.
• Scenario 2: Resource officer
• Scenario 3: 5-10 percent of work force has concealed carry
• Scenario 4: 5-10 percent of work force has concealed carry and a resource officer

In study number one, it was determined that the most crucial aspect is time. The more time a shooter has, the more people he can kill.
Moving on to the second scenario, that includes an armed resource officer, casualties dropped by a whopping 66.5% and response time was cut by 59.5%.
In the third scenario, with 5%-10% of the workforce armed, there is a decrease in fatalities of when 5% of the workforce is carrying concealed weapons of 6.8% and response time is reduced by 5.4%. When 10% of the workforce is armed causalities dropped by 23.2% and response time was slashed by 16.8%.
But the most amazing statistic is that when 5% of the workforce is armed AND they have a resource officer present, the fatality rate drops 69.2% and response time improved by 57.9%. 
With 10% armed and a resource officer, the fatality rate drops by 70.2% and response time by 62.7%.
Dietz says he still has some work to do.  
He wants to see if in cases where there is no active shooter present, would the guns being carried by school personnel lead to violence in the schools.  
Since many schools have armed guards already, with no incidences of violence, his report will not aid the gun grabbing liberals.