DOI: 10.3886/icpsr39020
title: Investigating Root Causes of School Violence: A Case-Control Study of School Violence Offenders, Non-School Youth Violence Offenders, and Non-Offending Youths, United States, 1990-2020
title: Archival Version

description: This study investigated root causes of school shootings by using a case-control methodology to compare 157 adolescent school shooters (cases) to samples of two key comparison groups: 157 non-school adolescent shooting offenders and 157 non-offending youths who attended the same school as the school shooter (controls) in the United States between 1990 and 2020 (overall n=471). Specifically, the researchers compared:

Adolescent school shooters who committed shootings both fatal and non-fatal to
adolescents who committed shootings both fatal and non-fatal outside school grounds in the community.
Adolescent school shooters who committed homicide to adolescents who committed shooting homicides outside school grounds in the community.
Adolescent school shooters who caused non-fatal injuries to adolescents who committed non-fatal shootings with injuries outside school grounds in the community.
Adolescent school shooters to non-offending students from the same school.

All groups were compared on items theorized to be risk and protective factors to crime based on major criminology theories, such as social learning, general strain, social control, bio-social, life course, and psychology. Building upon the methodology used in The American School Shooting Study (TASSS), this study relied on open-source, content analysis research methods to obtain all publicly available information on the sampled individuals. Files were collected from over 60 databases, major search engines, and archival resources, which were then reviewed and coded by the research team for evidence of risk and protective factors.
description: The purpose of this study was to identify risk and protective factors that distinguish adolescents who commit school shootings from non-offenders and from those who commit violent offenses in a non-school setting.
description: School shooter sample cases were sourced from The American School Shooting Study (TASSS), an open-source dataset that includes perpetrator-level, incident-level, and victim-level variables on every known firearm discharge that occurred on grade K-12 school grounds and resulted in at least one gunshot fatality or injury in the United States between January 1, 1990 and December 31, 2016. Additional cases between 2017 and 2020 were sourced with the same methods used to build the original TASSS dataset.
A case-control design was used to identify the comparison groups. For the community/non-school shooters comparison group, the team created sampling frames of 5 potential demographic matches for each school shooter. The team used the Newsbank search engine to discover articles on potential offenders based on the inclusion criteria. After 5 potential matches were identified, a random number generator was used to select a matched case for the dataset.
Similarly, for the non-offender student comparison group, 5 potential matches were created for each school shooter. The researchers used various online sources (Bing, Newsbank, online alumni listings) to identify potential matches. The random number generator process was used to select matched cases for the dataset.
To obtain data for the theorized risk and protective factor variables, the team relied on more than 60 databases, search engines, and archival sources, including chronologies/incident trackers, media aggregators, web-based newspaper archives, legal research services, law enforcement/corrections administrative sources, academic sources, People Search/White Pages, social media, public records, and criminal and background check services. Team members cross-checked search files with the project codebook to note evidence for any variables, then completed a case narrative noting important variables and overall quality of the search file.
description: Individual demographic variables: age, race, sex
Incident-level variables, when applicable:

Whether the incident was fatal or non-fatal
Year the shooting occurred
Total number of fatal and non-fatal gunshot injuries
Primary type of firearm used
Whether the shooting occurred inside a building

General strain theory variables, where the individual experienced one or more of the following:

A recent move or school transfer
Peer or friendship troubles
Peer aggression (i.e., bullying)
History of psychological issues
Suicidal ideation or attempts

Social bonding variables:

Parents' mortality and marital statuses at the time of the incident (or matching for non-offenders)
Individual's academic performance
Behavioral assessment in school (i.e., well-behaved, neutral, problems)

Social learning variables:

Whether peers engaged in delinquent or illegal behavior
Whether the individual had any co-offenders
Whether the individual was affiliated or associated with a street gang

Life course/criminal history variables:

History of impulsive behavior
Violent fantasizing (i.e., fascination with guns and other school shooters, discussing harming others, etc.)
Drug use
Prior offenses, arrests, and convictions
description: To be included in the school shooter sample, individuals were, at the time of the shooting, aged 13-19, enrolled students, and committed a shooting on school grounds that killed or injured at least one person within the United States between January 1, 1990 and December 31, 2020.
School shooters and non-school shooters were matched on the following: committing a shooting that killed or injured at least one person, county or region, time period of incident (same year or plus/minus 3 years), sex, and age (same or plus/minus 3 years). The differing factor was where the shooting took place (inside vs. outside school grounds).
Non-offenders were matched with school shooters based on school attended, sex, age (same or plus/minus 3 years), and time period attended the school (same or plus/minus 3 years).
For each group, 157 cases were included in the dataset, totaling 471.
description: Datasets: 
DS1: Investigating Root Causes of School Violence: A Case-Control Study of School Violence Offenders, Non-School Youth Violence Offenders, and Non-Offending Youths, United States, 1990-2020
description: Adolescent perpetrators of school-based shootings in the United States.
Adolescent perpetrators of non-school-based shootings in the United States.
Adolescent non-offenders in the United States.
.
description: record abstractsThis collection is related to Understanding the Causes of School Violence Using Open Source Data, United States, 1990-2016 (ICPSR 37935), alternatively titled The American School Shooting Study (TASSS). Please refer to the study webpage for more information on data sources and methodology. The variable <strong>MATCHID</strong> can be linked to <strong>MASTERFILEID</strong> in the TASSS data.