School Shootings: Better Data, Better Decisions

In August 2018, NPR Morning Edition asked the question, “How many times per year does a gun go off in an American school? We should know, but we don’t.” The story highlighted a lack of accurate and consolidated statistical data on school shootings.

To address this data void, the K-12 School Shooting Database has been created by the Homeland Security Advanced Thinking (HSx) Program’s co-founders (Desmond O’Neill and myself) as a research product of the Center for Homeland Defense and Security.

K-12 School Shooting by Category (ESRI Map)

The K-12 School Shooting Database contains more than 1,300 incidents from 1970 to present in which a gun is/was brandished, fired, or a bullet hit(s) school property for any reason, regardless of the number of victims (including zero), time, day of the week, or reason.

This definition, which is purposely more inclusive than exclusive, enables users to filter between subsets within the data (e.g., cause, number of victims, pre-planning, type of weapon(s) used, demographics, location) to conduct a more detailed analysis of incidents within their area of interest to make better informed decisions and generate more accurate reports.

Other School Shooting Data Sources

Prior to this database, the landscape of publicly available information compiled on school shootings arose from a wealth of sources including, but not limited to, peer-reviewed studies, government reports, archived newspapers, mainstream media, non-profit entities, private websites, personal blogs, and crowd-sourced lists. Individually, however, these platforms fail to capture the magnitude of the problem.

For example, government reports on school shootings by the US Secret Service, FBI, and Department of Education provide an explanation of factors contributing to shootings, but do not catalog a comprehensive list of the incidents. Lists of shootings reported by the media identify a large number of incidents, but provide few details beyond the date and location. Databases of school shootings on blogs and crowd-sourced websites have extensive lists of school shootings, but lack citations to any primary source. Without a common methodology for data collection, individual data sources are limited in both validity and utility. Furthermore, there is no consensus for what actually defines a school shooting to serve as the inclusion/exclusion criteria across the different datasets.

Research Methods

The data was collected from 25 different sources including peer-reviewed studies, government reports, mainstream media, nonprofit entities, private websites, blogs, and crowd-sourced lists. Prior to being include in the database, each incident has been filtered, cross-referenced and, when possible, validated against official records, such as police reports and court records. As new incidents occur or historical shootings are discovered they are added to the database using the same validation process.

Research Methodology

The K-12 School Shooting Database includes detailed information about each incident, a 1–5 reliability score that quantifies the dependability of the information, and the verified primary source citations (e.g., newspaper article, court records, interviews, police reports) to allow for further academic research.

Interactive Analysis Tools

The project’s website includes interactive Tableau graphics and charts. Users can include or exclude data from any of the visualizations.

K-12 School Shooting Incidents Per Year
Shooter’s Affiliation with the School

Questions and Additional Data

The database was developed from open-source information and is being continuously validated with official records.

If you have questions, corrections, or information about other incidents, please contact the research team. Follow us on twitter @k12ssdb.


David Riedman is an expert in critical infrastructure protection, homeland security policy, and emergency management. He is a co-founder of the Center for Homeland Defense and Security’s Advanced Thinking and Experimentation (HSx) Program at the Naval Postgraduate School.