The "conjecture" put in this study about the probable effectiveness of .410 pistols does not match the actual defensive shootings in Oklahoma using such weapons. Specifically, getting the assumed five buckshot hits with one shot is the rare exception. More likely, empty the gun and get one hit.
Also, most people who have come to our range with a Judge exhibit low marksmanship skills and don't seem to want to spend the money for extensive practice. The owner who uses it as a tractor gun and routinely shoots snakes with it learns to hit his target. YMMV.
You could also have put "study" in quotes.