These shootings occurred from 1980 to 2019. Seventeen contributing factors were considered, including lockdowns, types of weapons used, geography, and type of school. The most critical factors for the 133 shootings were:
- There were 134 shootings resulting in 419 injuries and 178 deaths.
- The ages of the 145 perpetrators ranged from 10 to 53; only 16 were aged 22 years or older, with more than one at 12 shootings.
- 70% of the perpetrators were current students, 15% were former students, 76% were white, and 98% were male.
- Various weapons were used, but assault weapons were the most lethal, with 4-fold more deaths and twice as many injuries.
- Lockdown drills had been used in 45% of the shootings, but there was no evidence of their effectiveness.
- There was no evidence that having an armed guard on the scene saved lives.
- These shootings occurred predominantly at public high schools and were approximately evenly divided among geographic regions and urban, suburban, and rural settings.
The authors concluded:
“After controlling for factors of location and school characteristics, the rate of death was 2.83 times greater in schools with an armed guard present… The majority of shooters who target schools are students of the school, calling into question the effectiveness of hardened security and active shooter drills.”
Source: Presence of Armed School Officials and Fatal and Nonfatal Gunshot Injuries During Mass School Shootings, United States, 1980-2019. JAMA Network Open 2021 DOI: 10.1001/jamanetworkopen.2020.37394.
