Guy Smith of Gun Facts has a great article titled “Good Guy with a Gun?” What jumped out at me was the response time vs. the casualty count. Guy calls it the police lag.
Looking at the graphs below (Figure 12 and 13) it becomes apparent that an armed resource officer that responds (not hiding behind a tree like the Florida school shooting) cuts the casualty count in half as compared to when the police arrive.
Another study (Mitigating Active Shooter Impact; Analysis for Policy Options Based on Agent/Computer Based Modeling, Kirby, Dietz, Sharevski, 2016) looked specifically at school shootings, and using the available empirical data, modeled a few things including the amount of time different defenders (cops, resource officers, people with concealed carry permits) would take to intervene and how many/few people would get hurt by the attacker.
He goes on to say:
Armed intervention by resource officers is very effective when, unlike at Parkland, they actually intervene. The time to response is short, and the number of people hurt is much lower. Too few schools have a significant number of armed faculty to have robust statistical evidence of efficacy, but the same dynamics are in play. Most (71%) of ASE and MPS attackers give up when confronted, by committing suicide or surrendering.
This definitely proves the statement as to why a trained, law-abiding citizen should carry a firearm: A policeman is too heavy to carry.
There may be other suggestions for protecting the students against an active shooter. I hate to admit that the following school safety suggestion comes from my home state of Pennsylvania. The Superintendent of Schools for Blue Mountain School District, Dr. David Helsel, testified before the Pennsylvania House of Representatives Public Education Committee Hearing (page 166):
…every classroom has been equipped with a 5-gallon bucket full of river stone. If an armed intruder attempts to gain entrance to any of our classrooms, they will face a classroom full of students armed with rocks, and they will be stoned.
In all fairness to Dr. Helsel, he does have a single armed resource officer for the entire district. He had two, but one retired. Maybe he needs to get and train at least one armed resource officer per school building.
A good guy with a gun makes a big difference.