As groups increase in size participation decreases, with the conversation centering on a talkative few. And as groups grow beyond five, members tend to complain that they are not able to participate as much as they would like and that as the group increases in size subgroups form, which may carry on annoying side conversations. With the increase in group size there is less time available for each member to participate; as the group increases linearly, the potential number of interactions increases exponentially. For example, in a dyad only two relationships are possible; in a triad there are nine possibilities; however when a group increases to 8, the number of possible interactions increases to over 1000.551
Based on the results of research findings and the observations of small-group discussion experts, it seems desirable to keep the group size to approximately five whenever possible so as to insure optimum participation, satisfaction, and efficiency. It may be advisable to include a few more than five in a group, allowing for the inevitable absenteeism. Of course this optimal size depends on the type or nature of the group. While five might be ideal for a problem-solving or discussion group, certain work groups or other types of groups might perform better with a different number of members.
Atkinson, Harley T. 2018. The Power of Small Groups in Christian Formation. Eugene, Oregon: Resource Publications.