Social network data consists of binary social relations. That
is, it records the presence, absence or strength of
relationships among pairs of persons. There are many kinds of
social relations. For example: Mathematically, social networks
can be represented as graphs or matrices. In this handout we
discuss graphs. A graph is defined as a set of nodes and a set
of lines that connect the nodes. This is sometimes written
mathematically as G=(V,E) or G(V,E). Here is one way to draw a
graph: |Figure 1. A drawing of a graph.| It is important to keep
in mind that the length of the lines does usually mean anything.
This is because all it is representing is that there is or is
not a relationship. Similarly, the orientation of the drawing
means nothing. For example, node e could have been placed in the
middle of the drawing -- this would not mean anything different.
The only thing that matters is who is connected to whom. There
are many synonyms for the terms "node" and "line": The nodes in
a graph represent persons (o