Schools that actively foster students’ sense of belonging and build strong relationships between adults and students are better positioned to prevent violent incidents. These are critical aspects of violence prevention, as most active shooters targeting schools are students, not strangers. Schools should create environments where students feel a strong connection to staff (reducing the likelihood that they will bring weapons to school), and can report threats to a trusted adult. Practices like mental health screenings and threat assessment can also help schools detect—and intervene—when students consider violence.

Security cameras, metal detectors, and other security measures may seem like natural deterrents for school violence, but little evidence suggests that they reduce or prevent its occurrence. In fact, in recent school shooting incidents, the perpetrators were able to gain access to the schools despite the presence of metal detectors or controlled access procedures. Security measures may also lead to unintended consequences: For example, they may increase students’ perceptions of fear and, for low-income schools, lower academic outcomes.

As of 2016, 57 percent of all public schools had either sworn police or security guards present at least once per week, a figure that rises to over 90 percent for the largest schools. However, research examining the effects of school police and security guards on school safety have had mixed results. Studies suggest that, when students trust school police, they are more likely to report incidents. But other studies have highlighted how the presence of police increases the likelihood of youth arrests for disorderly conduct and physical fights that educators would have otherwise addressed themselves. Further, the fact that active shooters have targeted schools where police were present—and have generally attacked schools to which they had a connection—suggests that security personnel may not be an effective deterrent. Families should ask whether security personnel (rather than educators) will address any student misbehavior, whether they may carry firearms or arrest students, and what training they must have before working in a school setting. Given disparities in school-based arrests by race and disability, families should also ask how schools will ensure equitable treatment of children.

As of 2018, at least eight states allow school staff to carry firearms, and an additional 17 authorize either schools or school districts to permit staff to carry firearms. After the Parkland shooting, legislators in at least 14 states introduced new policies to allow staff to carry guns, but very few passed. In some cases, states have enacted such policies to protect remote rural schools that law enforcement could not reach quickly in an emergency. However, families should note the dearth of available research to explain the implications of armed personnel for student safety, or the potential risks of firearms on school grounds. Experts generally advise against arming personnel due to concerns about potential safety challenges and skepticism that armed personnel will deter active shooters. Families should ask how firearms will be stored, when personnel may use firearms, and what training authorized personnel must have.

While evidence supports the effectiveness of drills and lockdown procedures, accountability and assessment are critical. In a study of one urban school district, most schools met the minimum requirement for number of drills, but almost half neglected to record evacuation times, and drills were not taken seriously nor assessed for improvement. Families should ask about how (and how frequently) schools practice emergency responses and the quality of the practice (e.g., diversifying drills by conducting them during lunch or between classes), as well as what steps staff are taking to continuously improve the process. Researchers caution against practices that are not evidence-based or those that can cause more harm than protection. For example, active shooter simulations have emerged since the Columbine shooting, but these may risk traumatizing students or desensitizing them to violence.