Results
This study examined a total of 133 cases of school shootings and attempted school shootings from 1980 to 2019. Perpetrators’ ages ranged from 10 to 53; however, only 16 shooters (11%) were aged 22 years or older. Ninety-four perpetrators (70%) were current students, and 21 perpetrators (15%) were former students. Of all perpetrators, 83 (76%) were White and 148 (98%) were male. Of 121 cases with full information, 57 (47.11%) were targeted shootings. There were 134 shootings, 12 with more than one shooter. A mean (SD) of 1.34 (3.25) people per case were killed and 3.15 (5.06) per case were injured, with a mean (SD) of 1.63 (1.22) weapons per shooting (primarily handguns; 68.66% [92 of 134]). An armed guard was on scene in 23.58% of shootings (29 of 123) (Table 1).
Based on theory, multivariate models include the presence of an armed guard and control for region, school type (public, nonpublic), and grade level (high school, elementary, other); location (urban, suburban, rural); use of lockdown drills; if the attack was targeted; total number of weapons brought to the scene; number of shooters; and weapon type. Results are presented as incident rate ratios in Table 2 and show armed guards were not associated with significant reduction in rates of injuries; in fact, controlling for the aforementioned factors of location and school characteristics, the rate of deaths was 2.83 times greater in schools with an armed guard present (incidence rate ratio, 2.96; 95% CI = 1.43-6.13; P = .003).
Discussion
This study had some limitations. It is limited by its reliance on public data, lack of data on community characteristics, and inability to measure deterred shootings (nonevents). However, the data suggest no association between having an armed officer and deterrence of violence in these cases. An armed officer on the scene was the number one factor associated with increased casualties after the perpetrators’ use of assault rifles or submachine guns.
The well-documented weapons effect explains that the presence of a weapon increases aggression.6 Whenever firearms are present, there is room for error, and even highly trained officers get split-second decisions wrong. Prior research suggests that many school shooters are actively suicidal, intending to die in the act, so an armed officer may be an incentive rather than a deterrent.4 The majority of shooters who target schools are students of the school, calling into question the effectiveness of hardened security and active shooter drills. Instead, schools must invest in resources to prevent shootings before they occur.
