Describing Networks

We can describe networks not only by their structure, but also by the patterns of relationships within them.

Popularity

Popularity refers to how frequently a node is connected to by others.

This is often measured using:

  • degree
  • or in-degree (in directed networks)

Popular nodes are often highly visible in the network.

Reciprocity

Reciprocity describes the extent to which relationships are mutual.

In a directed network:

  • A → B and B → A = reciprocal tie

High reciprocity suggests:

  • mutual relationships
  • two-way interactions

Transitivity

Transitivity describes the tendency for connected nodes to form closed triangles.

For example:

  • if A is connected to B
  • and B is connected to C
  • then A is also likely to be connected to C

High transitivity suggests:

  • tightly connected groups
  • clustering or community structure