Data from the Center for Homeland Defense and Security shows that school shooting incidents reached the highest level ever in 2021, despite many schools remaining closed at least part of the year due to pandemic restrictions with over 200 events. CHDS defines a school shooting incident as "every instance a gun is brandished, is fired, or a bullet hits school property for any reason, regardless of the number of victims, time of day, or day of week." An active shooter incident is described as a continuous episode of violence.