Online Program

Modeling Peer Effects and their Modification by an Actor’s Structural Prominence in a Social Network (306624)

Keywords: Peer effects , Effect modification, Social influence

We extend social influence analyses to allow peer effects to be modified by the structural importance of the focal actor's position in the network. This work is motivated by and applied to the diffusion of implantable cardioverter defibrillators (ICDs) in patients with congestive heart failure (CHF) across a cardiovascular disease patient-sharing network of United States hospitals. ICD diffusion is represented by three components: adoption of capability to implant ICDs, propensity to implant if capable, propensity of patients to receive ICDs elsewhere if not capable. Applying our novel methodology to study ICD diffusion across hospitals, we find evidence that exposure to ICD-capable peer hospitals is strongly associated with the chance a hospital becomes ICD-capable and that the direction and magnitude of the association is extensively modified by the strength of that hospital's ties to other hospitals in the network, even after controlling for effects of geography. Therefore, inter-hospital networks, rather than geography per se, may explain key patterns of regional variations in healthcare utilization.