My boss Elisa Bienenstock and I wrote a white paper on how Social Network Analysis can help forecast and detect rare events. It appears in Anticipating Rare Events: Can Acts of Terror, Use of Weapons of Mass Destruction or Other High Profile Acts Be Anticipated? A Scientific Perspective on Problems, Pitfalls and Prospective Solutions (N. Chesser, Ed.), which is an interdisciplinary review for operators in terrorism prevention within DoD/DHS/USG agencies.

In our paper, we focus on two insights from the field of social network analysis (SNA). First, innovation tends to happen at the periphery of social networks, rather than in a network’s core. New behaviors, insights, and events are more likely to occur when people with different backgrounds mix. Second, when a novel event involving new participants is being planned, we can observe signs of that activity in the network. New regions of the network will become active and new substructures will emerge. We conclude that an SNA-based approach for anticipating terrorism and other rare events would watch for two changes in structure: (1) new ties at the edges of networks, and (2) the new involvement of individuals with particular talents and resources with each other.