The Advanced Law Enforcement Rapid Response Training (ALERRT) Center at Texas State University has released a first-of-its-kind research report examining how schools can prevent, mitigate, and reduce the impact of active shooter events. Conducted in partnership with the Security Industry Association, the study analyzed 54 school-based active shooter incidents between 2000 and 2025, resulting in 324 victims.
The report, titled “The Role of Locked Doors and Access Control in School-Based Active Shooter Events,” evaluated attacker behavior, weapon types, lockdown procedures, entry methods, and door security conditions. It also included a deep analysis of the 2022 shooting at Robb Elementary School and the 2025 shooting at Evergreen High School.
Researchers found that unsecured doors played a major role in school shooting incidents. According to the study, 69% of successful perpetrator entries occurred through unsecured doors, while 61.7% of doors involved in incidents were unlocked or intentionally propped open. The findings also showed that the likelihood of a casualty was three times higher with unsecured doors than with secured doors. No functioning locked door in the dataset was successfully breached by defeating the locking mechanism.
The study highlighted that more than half of the shooting incidents occurred in high schools, while nearly 50% of attacks began in hallways or outdoor areas. Researchers also noted that although lockdown procedures were implemented in most incidents, some lockdowns were initiated only after attacks had effectively concluded.
The report emphasized that many security failures stemmed from preventable procedural gaps rather than sophisticated attacks. Recurring vulnerabilities included propped-open doors, inconsistent security practices, and inadequate maintenance procedures.
The research also identified differences in attacker profiles depending on school type. In middle and high schools, most perpetrators were current students, while elementary school attacks were carried out exclusively by outsiders.
The report outlined eight evidence-based recommendations for school administrators, policymakers, and security professionals. Recommendations included ensuring every classroom door has a functioning lock that can be engaged from inside the room, improving protection for glass features around doors, prioritizing maintenance and repairs as security functions, and strengthening procedural compliance and school security culture. Researchers also expressed concerns about aftermarket barricade devices and magnets, which they said can create safety hazards and operational complexity.
The study additionally underscored the importance of delaying attacker movement during incidents. Researchers found that even when attackers eventually breached entry barriers, secured classroom doors frequently slowed movement enough to allow lockdowns to begin, notifications to spread, and law enforcement to intervene.
The independent report was supported through a grant from the SIA Endowment Program. According to the organizations, the findings are intended to help school administrators, educators, law enforcement agencies, and policymakers evaluate school safety best practices and develop guidance programs nationwide.
The Security Industry Association will host a webinar on June 18 featuring insights from the research team and a deeper examination of the study’s implications for school safety.
KEY QUOTES:
“The central finding of this study is that secured doors are associated with substantially lower likelihood of casualties. Taken together, the evidence converges on a consistent conclusion: when doors are secured, the probability of harm to occupants behind closed door is substantially reduced. This recommendation is not novel, but the data presented in this report provide empirical grounding for a directive that has often relied primarily on expert consensus and anecdotal evidence.”
Report Authors, The Role of Locked Doors and Access Control in School-Based Active Shooter Events
“The most common way an attacker entered a space was not by defeating a lock—it was by walking through a door that should have been locked but wasn’t. Nearly two-thirds of the doors in our dataset were unlocked or propped open at the moment of attack. The hardware only protects students, teachers and staff when it is consistently used. The available data give empirical weight to a recommendation the field has long made on principle: lock the door.”
Hunter Martaindale, Ph.D., Director Of Research, ALERRT Center
