SNA 101: Network Density, Part 1 (Why Dense Terror Networks Prevail)

SNA 101 posts are meant to be instructional. If you are new here, please refer to the introduction before diving in!


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Why Dense Terror Networks Prevail

The common wisdom among national security experts is that al Qaeda, once a rigidly hierarchical organization, has become decentralized and distributed as a result of the ultraviolent and totally sweet coalition action against the Taliban shortly after 9/11. As a result, al Qaeda is no longer able to carry out sophisticated terror attacks and has instead opted to inspire its followers to carry out crude lone-wolf attacks. In this post and the following post, I will be using SNA to explain why this phenomenon has occurred.

Network density is probably the most fundamental network metric for understanding how networks tick. Calculating network density is pretty straightforward.

STEP 1: Determine the number of possible links in the network. That is, if every single actor in the network was directly linked to every single other actor in the network, how many links would there be? To figure this out, take the total number of nodes in a network (we'll call this n) and plug it into the following formula: n(n-1)/2.

STEP 2: Divide the number of actual links (we'll call this g) in the network by the number of possible links. In short, g/(n(n-1)/2).

You will get a number between 0.0 (no links exist, and thus, no network exists, and thus, you should not have gotten out of bed this morning) and 1.0 (every actor is linked to every other actor, and thus, every actor is virtually indistinguishable from one another, and thus, you should not have gotten out of bed this morning). Networks with a density closer to 1.0 are considered dense networks, while networks with a density closer to 0.0 are considered sparse networks. Let's look at some examples of a dense and a sparse network:

The sociogram on the left is a dense network. Every actor is directly linked to every other actor. If actor "2" wishes to communicate with actor "3," he can do so directly. For example:

2 to 3: Hey, man, you wanna' go see "Twilight" tonight?
3 to 2: Again?

The sociogram on the right is a sparse network. Each actor has only 1 or 2 links to other actors, which means that communication is a little more constrained... it has to pass from link to link until it gets to its recipient. If actor "2" wishes to communicate with actor "3," his communications must travel through actors "4," "1," and "5" before it gets to "3." You ever play that game in grade school where you sit in a circle and whisper a secret message to one another, and by the time it gets to the last person, a quaint message about the weather has transformed into shocking allegations about barnyard animals? We'll go ahead and refer to this as logistical failure. The more sparse the network, the more prone it is to this kind of thing. What's worse is that the chain of communication is easily disrupted. In the sparse network, if actor "1" is killed or captured, then actors "2" and "4" have no way of contacting actors "3" and "5." But in the dense network, if actor "1" is killed or captured, chances are good that no one will even notice.

This is why sparse networks cannot carry out sophisticated attacks such as simultaneous embassy bombings or simultaneous plane hijackings. It takes a dense network to pull that off. A structural reason that dense networks can carry out sophisticated attacks is the presence of cliques: highly connected subgroups of 3 or more members within a network. If you take a look at the dense sociogram on the left, you can probably spot a bunch of potential cliques. For example, "1," "2," and "4," (crudely highlighted below) are all connected to one another, which means that they can break off and work on projects together (such as building a bomb) without having to worry about logistical failure. Meanwhile, actors "5" and "3" can work on other tasks (like target selection) and check in with the bomb-making committee whenever they need to.

 Of course, this super dense network contains A TON of possible cliques of 3 or 4 actors, which means that it could contain many different subgroups or subcommittees dedicated to working on different tasks. The chart below breaks down this network into a handful of possible cliques we're likely to see in a modern day sleeper cell:
You now have a structural understanding about why dense networks are so much better at getting things done:

DENSE NETWORKS FACILITATE AWESOME ACTS OF TERRORISM BECAUSE:

1) Direct links amongst all or most actors ensures rapid and reliable communications.
2) The presence of numerous subgroups facilitates sophisticated and simultaneous actions.
3) The loss of any single actor will not disrupt communications.


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Knowing all this, why would an aspiring terror cell EVER opt for a sparse network? I'll address that, and more, in the next post, " Why Dense Terror Networks Fail"...