anizations, there has been a parallel interest in enhancing productivity by eliminating from these groups those "dysfunctional behaviors that interfere with the attainment of desirable interpersonal and task outcomes" (Greenbaum, Kaplan, & Damiano, 1991, p. 127). Several models of group effectiveness (see, e.g., Gladstein, 1984; Greenbaum, Kaplan, & Metlay, 1988; Hackman, 1987; McGrath, 1984, 1986; Tubbs, 1984) have drawn from systems theory to specify the various inputs and processes contributing to such desired group outputs as productivity, member satisfaction, and task accomplishment, as well as the feedback loops by which information about a group's outputs may affect its future inputs and processes. McGrath (1984, 1986) has particularly emphasized group process, or group members' interactions in relation to their task and performance situation, as a keystone to group effectiveness. Indeed, as early as 1972, Steiner noted that process losses, or faulty coordination of group members' efforts, could compromise group efficiency and effectiveness.
Hackman (1987) also addressed the importance of effort. In addition to having task-requisite knowledge and skills, as well as task-appropriate performance strategies to minimize the process losses Steiner (1972) observed, Hackman specified that group members must apply enough effort to execute their task successfully. To attain the process criterion of sufficient effort, Hackman prescribed an organizational context that supports and rewards group work, and an engaging group task and expert help to guard against "social loafing."
This reduction in individual effort that often occurs in groups (Steiner, 1972) was coined the social loafing effect by Latane, Williams, and Harkins (1979), after they found that individuals working alone shouted and clapped harder than those performing in groups. Social loafing effects have since been replicated on tasks requiring physical and perceptual effor...