Abstract
We theorize that the effect of membership turnover on group processes and performance depends on a group's communication network. We describe two mechanisms through which communication networks affect group performance: (1) the number of direct communication paths and (2) the clarity of the coordination logic. These mechanisms map onto two network dimensions: density, which affects a group's behavior through the number of available communication paths, and centralization, which affects a group's behavior through the clarity of the coordination logic. We empirically analyze the effects of turnover on the performance of fully connected all-channel networks and hub-and-spoke or wheel networks in an experiment of 109 four-person groups performing two collaborative problem-solving tasks. The greater number of direct communication paths enabled fully connected groups with stable membership to develop stronger transactive memory systems (TMSs) and perform better than fully connected groups that experienced turnover. By contrast, the clear coordination logic of perfectly centralized groups that experienced turnover facilitated more frequent dyadic communication, which enabled them to strengthen their TMSs, incorporate the contributions of new members, and improve their performance. Thus, our results indicate that communication networks condition the effect of membership turnover on group processes and performance.