This post is based off an "After Action Report" on school security. The scenario of this experiment to collect data is as follows:
The simulated school was populated with 10 human-operated teachers and 20 human-operated students, as well as more than 300 non-player character students to fill out the student body. A human-operated school administrator handled communications through the front office. In several of the runs, a human-operated SRO patrolled the school. Participants were recruited based on their real-world experience in these roles. At the scenario start, operators were instructed to perform actions that model a school morning. Ten of the classrooms were designated homerooms. Each teacher was assigned to a homeroom, one teacher per homeroom. Two human-operated students were also assigned to each one of these homerooms.
Prior to a threat, students and teachers were given assignments to circulate around the school on the way to their homerooms. During a threat, all participants were instructed to follow lockdown procedures as assembled from best practices of real school emergency procedures.
For each run, the shooter’s mission was to either target a particular homeroom teacher or inflict as many injuries as possible. Analysis found that varying the shooter’s mission had no significant effect on scenario outcomes in this experiment.
For ease, I am going to highlight a few things found in the report dealing with SRO's.
On average, casualties were 7 percent of the total population when the SRO was present as opposed to 13 percent when the SRO was absent.
On average, the shooter discharged 52 percent of ammunition when the SRO was present as opposed to 91 percent when the SRO was absent.
On average, 26 percent of students achieved safety when the SRO was present as opposed to 18 percent when the SRO was absent.
On average, 50 percent of homerooms (5/10) completed lockdown when the SRO was present as opposed to 30 percent (3/10) when the SRO was absent. In survey feedback teachers reported closing their doors when they saw the SRO was nearby.
For more data, please see the below report. This is good stuff for anyone who thinks they don't need an SRO in school.