A mass shooting is defined as four or more injured or killed by the Gun Violence Archive.
https://www.keranews.org/post/el-paso-shooting-249th-mass-shooting-2019
FBI is better to not include gangs etc.
That kind of stat is nonsense. The definition is understood by most of us to NEED a specific purpose to kill multiples. Many common thugs INCIDENTALLY shoot other people either carelessly or getting caught in the crossfire between gang thugs. Sorry, these are not classic “mass murders” in my view.