Why Groups are less Effective than their Members: On Productivity Losses in Idea-generating Groups

There is pervasive evidence that people produce more ideas and more good ideas when working alone rather than in groups. This chapter will first review the evidence for the productivity loss in brainstorming groups and then evaluate the various theoretical explanations which have been offered to account for these findings in the light of empirical research. This evidence suggests that the productivity loss in idea-generating groups is caused mainly by mutual production blocking due to the constraint on groups that members can talk only in turn. We then discuss various strategies that have been developed to overcome the disruptive effects of production blocking. However, since so far even the most successful strategies have raised the productivity of group members only to the level they would have achieved if they had worked individually, our final section discusses an ‘illusion of group effectivity’ as a reason for the persistence of the belief that group discussions are an effective means of generating ideas.