Much research has been done on team size. It has been found that large teams can be detrimental to team processes. Large teams allow for social loafing, an issue which will be further discussed later in the unit. Apart from the inequity in this behaviour, an overall effect is a decreased average participation rate. Low cohesion is a general occurrence in large teams whether some members are loafing or not. In large teams there is a tendency for a few people to dominate. Alternative ideas to the dominant ones are given less weight. Also, as teams get larger there is a greater tendency to use formal procedures in order to overcome the reduced cohesion.

So how big should a team be? This may seem an obtuse question to ask because, of course, it depends on so many things, like the nature of the task, or the context and purpose of the team. However, there is some consensus that teams of five to seven are the optimal size for problem solving. Coutu and Hackman (2009), who summarised the literature on team size, argue that 'single digits' are better. Hackman specifically claims that the bigger the team the more the links between team members that need managing and that can prove to be problematic. However, this causes problems for committees and executive teams where there is pressure for inclusion and representation. Involving all parties who have a right to be present may decrease the effectiveness of the team. Where it is necessary to have a larger team, some of the potential disadvantages can be counteracted by making individual contributions more visible, and by specifying more clearly what each member is accountable for.