Basic Network Concepts, Part II
WHOLE SOCIAL NETWORKS
IN THE PREVIOUS section, some basic concepts were introduced about nodes and the relations between pairs and triads. Key concepts that informed the discussion were homophily (the tendency of pairs of nodes to share the same characteristics) and balance (the tendency of the third in a triad to share or have a characteristic that complements the other two). Important as these ideas are, the essence of social network theory and analysis lies in a consideration of an entire network, to which we now turn.
A sociogram, the graph or diagram of a whole network, examples of which were shown in the first chapter, is one way to understand an entire network. As Yogi Berra reputedly said, “You can observe a lot by watching.” However, sociograms that contain more than ten nodes are hard to grasp and subject to different interpretations depending on who is “watching.” Analytic concepts and methods that account for the entire network and describe and summarize various aspects of it are necessary. Distributions of network properties are the first set of key descriptors and include the number of dyads and triads in the network. Other distributions discussed in this chapter include: Density, the number of connections contained within the network, and its opposite, Structural Holes, a category concerned with the lack of connections. A related concept, Strength of Weak Ties, hypothesizes that important things flow from people with whom one has limited connections. Popularity and Centrality demonstrate that some nodes have more connections than others and those connections serve as links to other nodes. Other distributions describe the Distance across the network between nodes. The radius of distances from any given node is an important descriptor. In terms of people, those nodes