Structural Cohesion and Embeddedness: A Hierarchical Conception of Social Groups

While questions about social cohesion lie at the core of our discipline, no clear definition of cohesion exists. We present a definition of structural cohesion based on network connectivity that leads to an operationalization of a dimension of social embeddedness. Structural cohesion is defined as the minimum number of actors who, if removed from a group, would disconnect the group. This definition leads to hierarchically nested groups, where highly cohesive groups are embedded within less cohesive groups. An algorithm developed and implemented (by Authors) identifies these nested groups by levels of structural cohesion, and thus measures the maximum levels of structural cohesion possessed by individuals as members of structurally cohesive subgroups. We discuss the theoretical implications of this definition and demonstrate the empirical applicability of our conception of nestedness by testing the predicted correlates of our cohesion measure within high school friendship and interlocking directorate networks.