The larger the terrorist cells, the easier to foil the plot: RMS modelling

An excessive number of terrorist operatives involved in attack planning might actually decrease the chance the operation will be carried out successfully, according to RMS risk modelling of terrorism risk pools.
At the June 2010 OECD Conference, ‘Terrorism Insurance in 2010: where do we stand?’ Gordon Woo, a catastrophe risk consultant for RMS, presented figures suggesting that small terror cells stand a much better chance of carrying out a successful terrorist attack than larger operations.
“An excessive number of operatives involved in an attack planning, increases the chance that an external link may compromise the operation, and lead to it being interdicted,” one of Woo’s presentation slides reads.
“In the past few years, the only successful Jihadi terrorist attacks in countries with high security have involved a modest number of operatives. Large plots involving many operatives have been interdicted.”
Woo cited statistics noting that for a cell of ‘x’ number of operatives, the number of external contacts for that cell would be in the range of three to 10 times the value of ‘x.’
So for a cell of one person, for example, the operative may have a range of 3-10 external contacts with whom he or she might be communicating by phone, email, post, meeting or accessing Jihadi Web forums.
The plot interdiction probability for a cell size of just one is 26%, according RMS’ numbers, which jumps to 78% if the cell has five operatives. The interdiction rate increases to 95% if a terrorist cell includes 10 people.
Typically, car bomb plots involving 600-pound bombs involve a cell size of about two people, according to RMS numbers. Plots involving 10-ton bombs occur with a frequency of only 0.4%, and feature cell sizes of 10 people.
Woo notes an aviations explosives plot requires far fewer operatives than the 19 it took to carry out the commercial airline hijacking that led to the Sept. 11, 2001 attacks on the World Trade Centre and the Pentagon.
Each of the 19 plotters in the 9-11 incident were just two degrees of separation away from two original Saudi al-Qaeda suspects monitored by the CIA in 2000, Woo noted.