NIH and CDC promulgated and/or funded utterly bogus research in the late 1980s and 1990's that claimed households with a firearm were more dangerous. In reality households with firearms and no criminal domiciled are about 30% safer than homes with no guns. Every one of those CDC or NIH funded studies ignored available  data on whether the owner of the firearm was a historic criminal who illegally owned a firearm, or active criminal with an illegal firearm. That turned out  to be over 90% in all cases of shootings: shootings of or by children, accidental shootings, and assault or murder shootings. In fact the risk of a knifing murder in a household increases 1,800 if a criminal is domiciled in the home. Over 70% of gun incidents happen in homes with persons who have 10 or more arrests ("super predators").