Social network analysis and counter-terrorism: measures of centrality as an investigative tool

This paper addresses the question of whether social network analysis (SNA) measures of centrality might be useful as an investigative tool. It is often asserted that SNA can help to identify key players in a network who should be targeted in order to disrupt organizational activities. This is explored here by first considering various practical obstacles, followed by an empirical test of how centrality measures perform against known behavior of an actual terrorist network. The analysis suggests that measures of centrality were at least superficially able to identify individuals in key network positions (facilitators and group leaders) and also tended to highlight particular cells at times of operational importance. However, SNA measures otherwise failed to identify hierarchies, and results were heavily dictated by group size and intra-connectivity, rather than genuinely reacting to operational behavior. Along with other shortcomings, these limitations mean that smaller or less well-connected groups and individuals are more likely to be overlooked, despite the fact that they can make significant contributions to both network functioning and disruption.