This hypothesis argues that the high prevalence of homicides in the US South
> stems from the fact that it was a frontier region settled by people whose
> economy was based on herding: the Scotch-Irish.
>
This myopic focus on agricultural types ignores everything else about the Scotch-Irish. As one who shares their blood (among a few other kinds), I think their historical origin, as the frontline shock troops of settlement and displacement, first in northern Ireland, then in America, is a bit more significant. A claim ignoring this history strikes me as about as sensible as a study setting out to prove that Zionist settlers in the West Bank tend to be violent because some of them herd sheep and goats.
-- "Hige sceal þe heardra, heorte þe cenre, mod sceal þe mare, þe ure mægen lytlað."