What Do Workplace Wellness Programs Do? Evidence from the Illinois Workplace Wellness Study (PDF)
Damon Jones, David Molitor, and Julian Reif

Workplace wellness programs cover over 50 million workers and are intended toreduce medical spending, increase productivity, and improve well-being. Yet, limitedevidence exists to support these claims. We designed and implemented a comprehensiveworkplace wellness program for a large employer with over 12,000 employees, and ran-domly assigned program eligibility and financial incentives at the individual level. Over56 percent of eligible (treatment group) employees participated in the program. We findstrong patterns of selection: during the year prior to the intervention, program partic-ipants had lower medical expenditures and healthier behaviors than non-participants.However, we do not find significant causal effects of treatment on total medical expendi-tures, health behaviors, employee productivity, or self-reported health status in the firstyear. Our 95% confidence intervals rule out 78 percent of previous estimates on medicalspending and absenteeism. Our selection results suggest these programs may act as ascreening mechanism: even in the absence of any direct savings, differential recruitmentor retention of lower-cost participants could result in net savings for employers.