Last week in Highlands Ranch CO, one student lost his life in another school shooting. It could have been much worse, had some students not tried to stop one of the killers. During the fight, one student, Kendrick Costillo lost his life. One precious life is one too many.

Each time a school shooting happens, parents ask the same questions: How do we keep this from happening again? How can my children be as safe as they can possibly be at school? If there was an easy answer, we would have likely solved it by now, but there is no easy answer. School safety is a multi-layered problem with multi-layered solutions.

After school shootings, we rightly hear the cries, “Something must be done!” Similar to the aftermath of the 2018 massacre at Marjorie Stoneman Douglas High School in Parkland FL, schools need to address what went wrong, and every school across the country needs to learn from their failures. The 480-page Marjorie Stoneman Douglas report should be required reading for all school administrators.

Our answer to, “something must be done,” should focus only on those things demonstrated to make schools safer.

Schools need to address physical building security, the mental health needs of students, threat assessments, rigorous support of Safe-2-Tell, and an armed presence on campus —even if that armed presence is in addition to School Resource Officers (SROs). In hundreds of school districts nationwide, that means armed school staff: teachers, principals, secretaries, janitors, bus drivers, coaches, and even cafeteria workers.

Researcher John Lott, author of More Guns, Less Crime just released a new paper answering the question: Do armed staff policies make schools safer? Do they prevent school shootings?

Lott’s research examined all shootings on K-12 campuses from January 2000 through August 2018 to determine whether the presence of armed school staff acts as a deterrent to school shootings. Lott’s conclusion is that while the trend line of people killed on K-12 campuses is increasing, the trend line of people killed on campuses that had armed school staff is zero. Lott concludes that if the armed schools had their “share” of school violence, they might have lost 13 lives, and had another 18 children and staff injured. Those are some pretty big numbers if your precious children are in those schools.

In addition, members of law enforcement —those who see crime on a daily basis— believe that legally armed citizens would have reduced casualties in mass killing events. According to a 2013 PoliceOne.com survey on gun policy, a full 80% of respondents said that casualties would have likely been reduced by the presence of armed citizens, and an additional 6% responded that casualties would have likely been eliminated.

Lott’s research also looked at some of the potential dangers that opponents of armed school staff are concerned about. Those concerns include negligent discharge of a firearm by an armed staff member, the possibility of a student getting a hold of an armed staffer’s gun, and an armed staffer accidently shooting a bystander. With the exception of a 2014 negligent discharge in Utah involving a firearm discharged in the faculty bathroom after school hours that resulted in only a minor injury, none of these concerns has happened. Although it’s good to look at “what-if” scenarios, they are not happening in practice.

The trend lines are clear: Schools without armed staff have increasing deaths. Schools with armed staff have zero deaths. Which schools do you want your kids and grandkids to attend?