Peer Effects on Physicians' Participation in Online Medical Teams: A Social Comparison Perspective

Online medical teams in online health communities (OHCs) are positioned as a scalable solution for collaborative care and hierarchical medical reform. Yet physician participation in these virtual teams remains unexpectedly low, even among senior physicians who are essential for team legitimacy and junior physicians who have the most to gain. This disconnect is not easily reconciled with incentives and institutional structures, pointing to peer effects and social comparison as overlooked drivers. Drawing on peer effects and social comparison theory, this study investigates how physicians' decisions to join teams are influenced by their peers' prior team-joining behavior. Using a three-year panel dataset of 491,943 physicians from a leading OHC in China, we combine propensity score matching with a difference-in differences design and robustness checks, and find that physicians are more likely to join online medical teams when their peers have done so. Contrary to expectations, this effect is weaker among senior or highly experienced physicians. Peers' recommendation ratings attenuate team-joining, whereas the number of patients in a peer's team does not significantly moderate the peer effect. Theoretically, this study extends social comparison theory in platform-enabled virtual teams by showing that professional hierarchy conditions how physicians respond to visible peer participation and status cues (e.g., titles and ratings) in OHC based online medical teams. Practically, the findings inform the design and governance of socio-technical systems in healthcare by motivating segmented peer-visibility strategies and careful management of reputation signals to avoid comparison backfire, offering actionable guidance for OHC operators and managers.