Mass shooting

A mass shooting is a violent crime in which one or more attackers use a firearm to kill or injure multiple individuals in rapid succession. There is no widely accepted specific definition, and different organizations tracking such incidents use different criteria. Mass shootings are characterized by the targeting (sometimes indiscriminate) of victims in a non-combat setting, and thus the term generally excludes gang violence, shootouts and warfare. Mass shootings may be done for personal or psychological reasons, such as by individuals who are deeply disgruntled, seeking notoriety, or are intensely angry at a perceived grievance; though they have also been used as a terrorist tactic, such as when members of an ethnic or religious group are targeted. The perpetrator of an ongoing mass shooting may be referred to as an active shooter.

The number of people killed in mass shootings is difficult to determine due to the lack of a commonly agreed upon definition. In the United States—the country with the most mass shootings—there were 103 deaths in mass shootings in 2021 (excluding the perpetrators) using the FBI's definition, and 706 deaths using the Gun Violence Archive's definition. Mass shootings are relatively rare in China, Singapore, South Korea, Japan, the United Kingdom, Russia, and across Africa.

It is common for mass shooting survivors to suffer from post-traumatic stress disorder and survivors guilt. After mass shootings, some survivors have written about their experiences and their experiences have been covered by journalists.

Mass shootings (that occur in public locations) are usually committed by deeply disgruntled individuals who are seeking revenge as a motive, for failures in school, career, romance, or life in general. Additionally, or alternately, they could be seeking fame or attention, and at least 16 mass shooters since the Columbine massacre have cited fame or notoriety as a motive. Fame-seeking mass shooters kill on average more than twice as many people as mass shooters who are not fame-seeking; many of the former articulate a desire to surpass "past records".

Media behavior covering to mass shootings have been blamed for instigating further instances. Mass shootings have also led to debates about and changes to gun legislation.