RPM Special Edition on School Violence:
In-Depth Exploration of Incidents

Last Updated: March 27, 2013

This article appeared in the RPM Special Edition on School Violence. The complete report is now available as a PDF; click here for details and to download or print.

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Special Edition on School Violence

This report represents some 700 incidents in which someone died or there was a threat to multiple individuals in a school setting. These incidents resulted in just under 600 deaths.

This section of the report presents additional information about patterns in the incidents.

Mass Violence Events

For this report, we defined Mass Violence as those incidents that claimed at least three victims (death and/or injury), or were random or open fire events that were intended to claim multiple victims and resulted in at least one injury.

We found 80 such incidents in U.S. schools since 1974. This category includes all the well-known school “massacres.” It also includes lesser-known events with multiple injuries but few or no deaths, incidents that have received far less general media attention. In addition, it includes several events that resulted in multiple injuries or deaths that occurred at school events (like ball games and dances) or while students were traveling to and from school.

If the perpetrator/s of the Mass Violence incident committed suicide as part of the event, the suicide is included in the total death count and not tallied separately.

These 80 events accounted for a little over 10% of all school violence incidents and about 25% of all school violence deaths in this report.

Click here to see a chart of the 80 Mass Violence school events included in this report.

Number of Deaths and Injuries
Total Deaths: 155  
Total Injuries: 448  
Incidents by School Locale
Mass Violence incidents have occurred in all kinds of communities and locales.
Rural: 13%  
Small Town: 13%  
Suburban: 29%  
City/Urban: 45%  
Incident by School Level
Mass Violence school incidents occurred in all school levels.
High schools: 60%  
Middle schools: 20%  
Elementary schools: 20%  
Death by Weapon: 155 total deaths
The overwhelming majority of deaths in Mass Violence incidents were gun-related. In fact, we found only one incident in which victims died from anything other than gunshot wounds. In that event (Costa Mesa, CA, 1998–99), a 39-year-old man deliberately drove a car onto a playground with the intent of killing children. Two children died, and four children and one adult were wounded.
Gun: 153  
Stabbing/slashing: 0  
Other (Costa Mesa, CA): 2  
Injury by Weapon: 448
Many more victims were injured than killed in Mass Violence events. Again, the most dangerous weapon was a gun. In four instances, the perpetrator used knives or machetes, injuring 34 victims. In one event (Cokeville, WY, 1985–86), a man and his wife used guns to take dozens of children and teachers hostages; before committing suicide, they set off a bomb that caused burn injuries to 79 victims.
Gun: 76%  
Stabbing/slashing/other: 7%  
Explosives (Cokeville, WY): 17%  
Perpetrator Age, All Mass Violence Incidents
Students, including several who were 13 or younger, were the perpetrators in more than half of Mass Violence events.
13 years old or younger: 6%  
14–15: 23%  
16–17: 17%  
18 or older student: 5%  
Teen, age not given: 5%  
Group: 3%  
Adult (18 or older, non-student): 24%  
Unknown: 14%  
Police/Other Officer: 3%  

There were, however, important differences in perpetrator age between elementary school and middle and high schools, with adult intruders much more likely to target elementary schools.

Perpetrator Age, Mass Violence, Middle and High School
13 years old or younger: 7%  
14–15: 29%  
16–17: 20%  
18+ student: 7%  
Teen, age not given: 7%  
Group: 4%  
Adult: 10%  
Unknown: 15%  
Perpetrator Age, Mass Violence, Elementary School
All Mass Violence incidents in elementary schools were committed by adults, except one incident, San Diego, CA, 1978–79, in which a teenaged girl shot onto a playground from across the street.
13 years old or younger: 0%  
14–15: 0%  
16–17: 6%  
18+ student: 0%  
Teen, age not given: 0%  
Group: 0%  
Adult: 94%  
Unknown: 0%  

Single Events

Single events accounted for the largest percentage of incidents and the largest number of deaths. Single events are defined as those in which one or two people died. The perpetrator, if identified, targeted victims personally (as opposed to randomly). The Single event category also includes incidents with one or two deaths in which the perpetrator is unknown. In these unknown cases it is often impossible to know if the victim was targeted. Sometimes victims were accidentally caught in crossfire, hit by stray bullets, or misidentified as someone else. In these incidents the assailant did not appear to be targeting multiple victims at once.

Most deaths occurred as a result of gun attacks. We did not track the types of guns used. We note, however, that in many accounts the weapon was reported as legally owned by someone in the perpetrator’s family.

Assailants used a variety of implements in stabbings and slashings, primarily knives of one sort or another, but also machetes, scissors, art tools, screwdrivers, and other items.

Single events are divided between those that occurred on campus, at school events, and on school buses (Single, On-Campus), and those that occurred off campus (Single, Off-Campus) while students were traveling to school or a school event by some means other than a school bus.

Single, On-Campus: This category includes all incidents that occurred on the school grounds during the school day, including opening and dismissal of school. In addition, it includes incidents that occurred at school events, on school buses, and at school bus stops.

Violent school deaths occurred on all parts of school campuses — in classrooms, cafeterias, playgrounds, ball fields, hallways, and parking lots. Deaths also occurred at school events, especially ball games, but also at dances, performances, and graduations. Many of these deaths occurred just after the event, on sidewalks and in parking lots, as participants were dispersing.

The Single, On-Campus category also includes suicides. School suicides are a small portion of all child and youth suicides. However, when they occur at school, suicides are frequently committed in front of other students. Suicides that occur in Mass Violence events are counted as deaths in that category and are not included here.

There were about 350 Single, On-Campus incidents. A few incidents were murder-suicides or double murders, resulting in a little more than 350 deaths.

Homicide: 75%  
Suicide: 25%  
Location of Incident
Most incidents occurred on campus.
On school grounds: (including parking lot) 84%  
Bus/Bus stop: 10%  
Event: 6%  
Death by Weapon (On-Campus): 443
Guns accounted for the majority of deaths in the incidents we identified.
Gun: 68%  
Stabbing/slashing: 20%  
Beating/other: 12%  
Incident by School Level (On-Campus)
Most incidents occurred in high schools.
High schools: 73%  
Middle schools: 19%  
Elementary schools: 8%  
Age of Perpetrator (On-Campus)
13 years old or younger: 9%  
14–15: 24%  
16–17: 24%  
18+ student: 8%  
Teen, age not given: 12%  
Group: 3%  
Adult: 10%  
Unknown: 7%  
Police/Other Officer: 3%  

Single, Off-Campus Travel: In some schools and districts, a majority of students (mostly at middle and high school levels) do not ride the school bus. Some districts, especially large metropolitan districts, do not provide student transportation to older students. When neighborhoods are violent, this creates a dangerous situation for students. Nearly 15% of deaths in this report occurred off campus while students were traveling to school, not on a school bus. Nearly half of these incidents involved an unknown shooter.

Most Off-Campus Travel incidents occurred in urban school districts. For a journalistic investigation of neighborhood youth violence, we recommend the “Harper High School” episodes, Parts One and Two of the radio program, This American Life.

Incident by Grade Level (Off-Campus Travel)
High schools: 88%  
Middle schools: 7%  
Elementary schools: 5%  
Death by Weapon (Off-Campus Travel)
Gun: 72%  
Stabbing/slashing: 20%  
Beating/other: 8%  
Perpetrator Age (Off-Campus Travel)
13 years old or younger: 1%  
14–15: 5%  
16–17: 8%  
18+ student: 0%  
Teen, age not given: 20%  
Group: 9%  
Adult: 10%  
Unknown: 47%  

Threatened Mass Violence: In addition to the 80 Mass Violence incidents that were carried out, we found nearly as many incidents of Threatened Mass Violence. These fell into two basic kinds of events. Failed attempts were incidents in which the perpetrator initiated a Mass Violence incident but was unable to pull it off. In several cases, weaponry (including a few incidents involving explosives) failed; in some instances, someone intervened before injuries occurred. There were also several incidents in which the perpetrator fired into the air or ceiling rather than at students; and there were several incidents in which a student committed suicide and investigators later discovered a stash of weaponry or ammunition that suggested the student had contemplated a mass action.

Averted attempts were incidents in which the perpetrator (almost always a student) was in the process of assembling the weaponry and plans to carry out a Mass Violence attack, but their plans were discovered and reported to authorities. In most cases a classmate, friend, or parent made the discovery. In a few cases, the student posted an online message calling attention to their plans. We included only those incidents in which the student had the means (weaponry and detailed plan) to carry out the attack.

Finally, there were a few accounts of incidents in which there was potential for a Mass Violence event, but circumstances or intent were unclear. In these cases, if a death were involved, we counted the event in the Single category; if there were no deaths, we counted the event in the Threatened Mass Violence category.

Total Threatened Mass Violence Attempts
Failed Attempts: 25%  
Averted Attempts: 75%  

Accidental Gun Discharges: Nearly 10% of all incidents that we discovered were accidental gun discharges. About 10% of these accidents resulted in death and are counted as Single events. The remaining accidents sometimes resulted in injury and sometimes they did not.

Initially, we noted accidental discharges as they came up in our review of incidents, but we did not intend to include them in this report. Like all injury-only incidents, they are much harder to track through media accounts, so we knew that including them would under-represent the frequency with which they occur in schools.

Ultimately, however, we decided it was important to include information about these incidents for two reasons. First, even though they are accidental, these discharges are a part of the school violence landscape. Although the person rarely intended to harm anyone at school, they often shot themselves or a friend.

Second, many of these incidents involve young children. In some cases the child brought the weapon for “protection,” in some cases as a toy, and in some cases the gun was left in the child’s backpack or other belongings by an adult and the child was not even aware of it.

Accidental Gun Discharges, By Grade Level
Elementary: 21%  
Middle: 18%  
High: 61%  

Hostage Events: Hostage taking is a fairly common component of Mass Violence and sometimes of Threatened incidents. We note it because the presence of hostages greatly complicates negotiations with the perpetrator. About 5% of all incidents we identified were events in which someone took hostages but the incident ended without physical injury. The majority of school hostage takers in these non-injury events were students.


Read more from the RPM Special Edition on School Violence.