Multiple team membership is common in today’s team-based organizations, but little is known about its relationship with collective effectiveness across teams. We adopted a microfoundations framework utilizing existing individual- and team-level research to develop a higher-level perspective on multiple team membership’s relationship with performance of entire units of teams. We tested our predictions with data collected from 849 primary care units of the Veterans Health Administration serving over 4.2 million patients. In this context, we found multiple team membership is negatively associated with unit performance, and this negative relationship is exacerbated by task complexity
