Influence in terrorist networks: From undirected to directed graphs

A methodology for converting terrorist networks from undirected graphs to simplified directed graphs (or digraphs), and mapping the flow of influence in them, is described. It is based on an "influence assumption"-that important persons with more links influence less important persons with fewer links. This methodology, which was previously used to analyze the structure of influence relationships in Communist-bloc countries and the international system, is illustrated by its application to two terrorist networks constructed after 9/11. In the second more complex network, the hierarchy sheds light on the leadership and likely terrorist cells embedded in the network. Refined data and alternative assumptions about influence could provide additional insights into the structure of terrorist networks.