Mike Masterson, the police chief in Boise, Idaho, feeds an email list that I subscribe to with some very interesting posts. He sent a link out this week to a fascinating analysis of mass shootings in the United States since 2006, from USA Today.
Not only is the analysis interesting, the techniques used for visualizing the data are impressive. The statistics come alive in this infographic, in a very powerful way. There is also an interactive database application with which one can query the dataset in several ways.