Group Compatibility - (Schutz, 1955, 1958) - His Fundamental Interpersonal Relations Orientation (FIRO) theory attempted to explain how the characteristics of each group member relative to the characteristics of each other group member influence group effectiveness.  Schutz hypothesized that the patterns of interactions among individuals can be explained largely in terms of three interpersonal needs: inclusion, control and affection.  From a group development perspective, as soon as a group is formed, the inclusion phase begins.  People have concerns such as whether they want to remain a group member.  After problems of inclusion are sorted out, control problems become the center of concern.  At this point, the issue of decision-making arises.  Each person in the group is attempting to structure the situation to achieve just the right amount of responsibility in the group.  Assuming that the control issues are resolved successfully, the group moves to the affection phase.  At this point, the group has been formed, and problems of responsibility and power distribution have been worked out, all that remains is the problem of emotional integration.  Each member is attempting to establish the most comfortable position possible with regard to affectional interchange.  The three phases are not discrete; all types of behavior occur in all phases.  However, the phases represent periods in the group's history in which particular problem areas are emphasized.

Group Motives & Goals - (Zander, 1971) - It is a common observation that groups form and continue to exist for some purpose, that is, to achieve some goal or goals.  Groups that have clearly established goals are usually organized, effective, and satisfying to their members, whereas groups that don't have such goals often engage in aimless activity, are ineffective and provide little satisfaction for their members.  Zander's work in this area examined topics such as group and individual goal-setting behavior, the effects of external pressures on group aspirations, individual desires for group achievement, relations between person-oriented and group-oriented motives, beliefs of group members as indicators of purposive group behavior,and  processes of evaluation of personal and group performance.

Group Process and Productivity - (Steiner, 1972) - The theory proposed by Steiner attempts to explicate the processes that influence the productivity of relatively small, task-oriented groups.  Steiner states that group performance depends upon three classes of variables: task demands, resources and process.  Task demands include the requirements imposed on the group by the task itself or by the rules governing task performance.  Resources include all the relevant abilities, skills, tools and the like that are possessed by persons attempting to perform the task.  Process refers to the steps actually taken by a group when attempting a task, including all those interpersonal and intrapersonal actions that group members engage in.  According to the theory, actual group productivity is equal to potential productivity minus losses due to faulty process.