SOCIAL NETWORKS Mapping interactions within and between

The structure of interactions and the pattern of influence in an organization can be characterized in terms of a map of interactions within and between cohesive subgroups. I extend the work of Festinger, Schachter and Back (Social Pressures in InformalGroups, 1950, Stanford University Press) who constructed a map based on the pattern of communi-cation within and between apartment courts. In order to generalize Festinger et al.'s approach, I substitute a posteriori subgroups for Festinger et al.'s apartment courts, and I replace the distances of a physical geography with those of a metric multidimensional scaling. I apply the technique to data indicating professional discussions among teachers in a high school. After confirming that discussions are concentrated within a posteriori subgroups at a level that is unlikely to have occurred by chance alone, I construct a map of discussions within and between the cohesive subgroups. The map allows me to characterize the processes of influence at the teacher and school levels through which the school responds to external conditions, and I argue that a map based on blocks of structurally similar actors does not sustain a comparable characterization. 1. Introduction: Mappin