When trying to understand American gun policy, there is at least 2 sides of the story. One deals with the epidemiological data: is there a link between, for instance, gun availability and homicides/suicides? This type of analysis, with strong controls and replication, can eventually give the danger of having guns at home or gun shops around the corner.
But we usually omit the other part of the story: what motivates people to carry guns in the first place? Stroebe, Leander & Kruglanski (2017) recently published a paper in PSPB reporting a two pathways models (perceive threats/diffuse threats) pre- and post- the Orlando shooting (deadliest in US history, 49 dead and 58 wounded). The population-level data showed us that the level of danger of a State/City is not correlated with the number of people owning a guns. As a result, the need for a psychological model underlying the processes at play seem crucial to see which pathways are influencable and which ones are not.