A primer on the relationship between group size and group performance

Living in groups can benefit individuals in many ways, including in innovative problem solving. Several hypotheses have suggested mechanisms to explain why larger groups disproportionately outperform smaller groups, including the skill pool and pool of competence effects. However, disentangling these potential mechanisms from the effects of group size alone has been challenging. Here, we first outline key ways in which group size can shape performance in innovative problem solving. We then detail the nonlinear nature of the mathematical relationship between group size and various measures of group performance. Finally, we use simulations to confirm that measures of group performance in innovative problem solving scale nonlinearly with group size, even in the absence of any other effect. Our study provides guidance on how best to evaluate hypotheses about group composition on innovative problem solving, and clarity to help future studies make appropriate assumptions when developing null hypotheses against which to test their empirical data.