One tie to capture advice and friendship: Leader multiplex centrality effects on team performance change

Because leaders' authority is often insufficient to change team performance, formal team leaders seek informal influence through the occupation of central positions in social networks. Prior research focuses on leader centrality involving simplex ties, that is, either friendship or advice, to the neglect of multiplex ties that involve the overlap of friendship and advice. Friendship and advice ties offer different but complementary resources, so leader centrality in one but not the other network limits leader influence. We provide theory and evidence concerning how leader multiplex centrality affects team performance improvement, particularly if leaders are embedded in team social contexts with sparse friendship and numerous adversarial ties. The research context involved 84 ongoing public university service teams headed by formal leaders. Our results show the importance of leader multiplex centrality relative to leader simplex centrality. First, leader multiplex centrality predicted team performance change over a 2-year period more strongly than leader centrality in either the advice or the friendship team network. Second, leader multiplex centrality positively predicted team performance change for teams featuring dense adversarial networks or sparse friendship networks. It is not sufficient, therefore, for leaders to be either liked or regarded as expert. It is the integration of both advice and friendship in one tie between the leader and followers that facilitates performance change.