See the updated map done by Updated by German Lopez and Soo Oh – with Mass shooting locations in the US since Sandy Hook.
Are these types of shootings increasing? It depends on which definition you use.
Using the definition many people operate under — shootings at a public place in which the shooter murdered four or more people, excluding domestic, gang, and drug violence — they appear to be getting more common, according to an analysis from Harvard School of Public Health researchers.
But not everyone agrees with this definition. Northeastern University criminologist James Alan Fox, for example, defines mass shootings as any shooting in which at least four people were murdered. Under those terms, mass shootings don’t appear to be increasing. Researchers from the Harvard School of Public Health call that definition too broad, since it catches domestic, gang, and drug-related shootings that aren’t usually considered mass shootings in layman’s terms.
But the Mass Shooting Tracker is even broader — counting not just shootings in which four or more people were murdered, but shootings in which four or more people were shot at all. The database’s organizers explained their reasoning on their website: “For instance, in 2012 Travis Steed and others shot 18 people total. Miraculously, he only killed one. Under the incorrect definition of mass shooting, that event would not be considered a mass shooting! Arguing that 18 people shot during one event is not a mass shooting is absurd.”
See the map which is kept updated.