Analysis of social structure has been advanced by the idea that social differentiation is defined by networks of social relations. Prior to the network approach to social structure, analysts relied on nominal classifications of actors (based on gender, race, ethnicity, religion, or occupation among other variables) to describe the social differentiation of groups, communities, and organizations. In the network approach to social structure, the positions of actors are revealed by their patterns of relations with other actors, and a differentiated social structure is defined by the existence of actors who occupy different positions in networks of social relations. The approach has been widely applied. For instance, it has been used to describe the social structure of elite families in Florence circa 1430, monks in a present-day monastery, major corporate actors in national markets and policy communities, and researchers in scientific specialties.

I build on this line of structural analysis. Social differentiation is my start point.