The Intersection of Social Circles

A common methodological approach to the study of networks is to define a measure of proximity or social distance from the network data. Generally, the definition of such a measure rests on some representation of the flow of communication between individuals in the network. This paper proposes a different basis for such a measure-patterns of loyalty and affiliation-and presents and describes such an appropriate measure, based on the overlap of interpersonal environments. The new measure is intended for application to the network study of social differentiation-for example, to the study of political elites-and is illustratively applied to data concerning networks of intellectuals.