mapping terrorist networks

A good way to understand how terrorist networks work is to map them. A well constructed map provides insight into how the network operates. In his paper, "Uncloaking Terrorist Networks" Valdis Krebs uses social network analysis to map the terrorist network that attacked on 9/11. Despite incomplete knowledge of all the connections between members, his analysis is still cogent and probably fairly close to reality. Here's what he found out about the networks structure:A larger administrative network to support the operational teams. The administration network provided a means to "keep alive" many of the weak connections between sparsely connected members of the operational network. They also provided much of the ongoing care needed to prepare an otherwise isolated operational team member for the attack.

A leadership structure despite a lack of formal hierarchy. When the network is looked at in its entirety (operational plus administrative), Mohammed Atta emerged as the leader. Atta had 22 connections to other people in the network, much more than any other (the nearest other outlier was 18). Mohammed Atta's position on the network gave him control of its operation. Atta scored high in all measures of network connectivity: degrees (activity on the network), closeness (his ability to access others on the network -- fewer number of hops), and betweeness (control over the network -- a central position that allowed him to broker the flow of information across the network).