Membership stability and performance: a study of baseball clubs and laboratory groups

This research aims to analyse the association across membership stability, group boundary and group performance. Using Professional Chinese Baseball League's data (Seasons 2003-2007), Study One reveals that the membership stability of baseball clubs was correlated with their annual rank and win-probability, and that stable teams outperformed unstable teams. Membership stability also predicted win-probability in four out of five seasons. Using undergraduate students, Study Two reveals that members from unstable groups (i.e. groups with higher membership turnover) had higher intention of leaving their groups and more departures. Members from stable groups had better group performance, group cohesion, and group dynamics, which all resulted in members displaying more trust in their colleagues and an increased willingness to cooperate with them. Implications of the findings include that stable membership is a crucial factor in the promotion of group dynamics and overall performance, and that the nature of a group's boundary affects its membership turnover. Policies should also be devised to manage membership stability, as maintaining an appropriate turnover rate is essential both to individuals and to groups, such as employees and their organizations.