text: Chapter 4
  degrees of centrality. A network centralized around a well-connected hub can fail abruptly if that hub is
  disabled or removed. A less centralized network has no single points of failure, and it has multiple
  connections between all members. It is resilient even if some nodes are removed. Many nodes or links can
  fail while still allowing the remaining nodes to reach each other over other network paths.
  4-96. Commanders and staffs can also understand how an individual fits into a network by looking at that
  individual’s degree centrality and betweenness centrality. Degree centrality describes how active an
  individual is in the network. Network activity for a node is measured using the concept of degrees—the
  number of direct connections a node has. Nodes with the most direct connections are the most active in
  their networks. Commanders and staffs determine where those connections lead and how they connect the
  otherwise unconnected. If a node has many ties, it is either prominent or influential. Betweenness centrality
  indicates the extent to which an individual lies between other individuals in the network, serving as an
  intermediary, liaison, or bridge. A node with high betweenness centrality has great influence over what
  flows in the network. Depending on position, a person with high betweenness plays a broker role in the
  network.
  4-97. Nodes on the periphery often receive very low centrality scores. However, peripheral nodes are often
  connected to networks that are not currently mapped. The outer nodes may be resource gatherers or
  individuals with their own network outside their insurgent group. These characteristics make them very
  important resources for fresh information that is not available inside their insurgent group.
  4-98. However, understanding a networked insurgency requires more than simply understanding
  relationships between individuals. Commanders and staffs must understand an insurgency at the
  organizational level. Organizational-level analysis provides insight about the insurgent organization’s form,
  efficiency, and cohesion. Commanders and staffs must understand a networked insurgency’s overall
  organization to understand the nature of the threat. An insurgency may consist of large numbers of
  subinsurgencies. As a result, each group will have a range of capacities as compared to the other groups.
  Commanders and staffs can describe organizational capacities using the concept of network density.
  4-99. Network density is a general indicator of how connected people are in a network. Network density is
  the proportion of links in a network relative to the total number of links possible. Network density within
  an insurgency indicates which groups are most capable of conducting a coordinated attack or other type of
  coordination. (See figure 4-5.)