Peer Effects in the Workplace: Evidence from the Illinois Workplace Wellness Study

We test for peer effects in the Illinois Workplace Wellness Study, a large-scale randomized controlled trial designed to investigate the effects of workplace wellness programs. We randomly assigned program eligibility and financial incentives at the individual level to 4,834 workers, and elicited information about their social networks (coworkers) at baseline. We find substantial network homophily across all our socioeconomic variables. Finally, we find that treating additional coworker peers increases an employee's probability of participating in the workplace wellness program.