Mother Jones senior editor Mark Follman spent the past year covering the recurring tragedies of mass shootings while researching his “Guide to Mass Shootings in America”—a first-of-its-kind, continuously updated dataset that Follman started in July 2012 after the Aurora movie theater shooting. In advance of the December 2013 anniversary of the killings in Newtown, Follman took on a new, especially devastating aspect of the guns beat: He led a group of reporters in documenting the children ages 12 and under who were killed by firearms in the year since the Sandy Hook tragedy. The team undertook an exhaustive analysis, scouring news reports to generate a comprehensive picture of the effects of guns on children in America. Their findings were stark: In the last year alone, guns killed at least 194 children—across 43 states, from inner cities to rural towns. Their average age: 6. The vast majority—127 in total—died in their own homes, with 72 children pulling the trigger themselves or being shot by another child and 60 dying at the hands of their own parents. As many cases don't make the news, Follman cites medical research that pegs the actual number of child deaths from guns to around 500 each year.