Mapping interactions within and between cohesive subgroups *

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 communication within and between apartment courts. In order to generalize Fest inger et al.'s approach, I substitute a posteriori subgroups for Fest inger et al.'s apar tment courts, and I replace the distances of a physical geography with those of a metric mult idimensional scaling. I apply the technique to data indicating professional discussions among teachers in a high school. Af ter 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.