The downside of co-author success in scientific collaborations

Research on scientific collaboration networks demonstrates that co-authorship enhances scientists’ performance, particularly when co-authors are prominent within the network. Yet, prior work largely adopts a static perspective, leaving limited understanding of how changes in co-authors’ prominence affect scientists. When co-authors engage in other research projects, this affects their network prominence and can influence scientists’ performance. Drawing on social network theory and research on scientific collaboration, we theorise that increases in co-authors’ prominence are associated with reduced performance for the focal scientist. We argue that when co-authors increase in prominence, they disperse their effort across projects, allocating less to the joint endeavour. The hypotheses are tested using unique data on 12,023 observations of 1,553 scientists collaborating on 4,433 papers. The results reveal a negative spillover: focal scientists’ performance declines when co-authors rise in prominence. This effect intensifies when collaborators also increase in performance but diminishes with greater knowledge domain overlap.