The purpose of this paper was to measure small groups at various stages of their development and observe the effects of changes in group process on emergence of role types and the impact these roles have on group membership as a whole. Most small group measuring instruments have been built around a task-leader or socio-emotional leader dichotomy. Lack of consistent direct relationship between the influence of individual members of the group and their position in the group suggests that an understanding of group leadership and power cannot be gained solely from a functional approach in a social influence perspective. The propositions and hypotheses of this paper are concerned with the general power a leader in a group holds over the membership throughout the group's life span. Proana 5 computer simulation was used to demonstrate the theoretical considerations of this paper in terms of small group interaction, providing a possible description of the interaction of on-going groups. (Author/LG)