Public HealthHuman capitalNull

Workplace Wellness Programs — Illinois RCT

University of Illinois / Harvard / National Bureau of Economic Research · University of Illinois, USA · 2016

Summary

The Illinois workplace wellness RCT is the largest and most rigorous test ever conducted of a $50B industry — and it found essentially nothing. Employees offered a comprehensive wellness program reported exercising more, but showed no difference in weight, blood pressure, cholesterol, smoking rates, absenteeism, job performance, or healthcare costs over 3 years. The null result is important precisely because it was conducted by researchers with strong incentives to find positive effects (the University of Illinois was the program's employer), used a proper randomized design with a control group, and pre-registered all 38 outcome variables. The most likely explanation is that wellness programs attract already-healthy, already-motivated employees (selection), and that the marginal effect on the harder-to-reach population — the one that would most benefit — is near zero. The study is a cautionary tale: behavioral interventions that feel consequential can produce no measurable population-level health change.

Research question

"Do employer-sponsored wellness programs — which cost US employers over $50B annually — improve employee health outcomes, healthcare costs, and productivity?"

Methodology

Intervention

The University of Illinois offered a comprehensive workplace wellness program to all employees. Among 12,459 benefit-eligible employees, 4,834 were randomly selected to be offered the program (treatment) and 7,625 were not offered it initially (control). The program included health screenings, goal-setting, financial incentives for healthy behaviors, fitness challenges, and online modules covering nutrition, stress, sleep, and chronic disease management. The study ran for 3 years.

Assignment

Randomized controlled trial; employees randomized at the individual level to treatment (offered wellness program) vs. waitlist control; Jones et al. (2019) published in Quarterly Journal of Economics; widely considered the most rigorous workplace wellness RCT ever conducted

Sample size

4,834 treatment; 7,625 control; 3-year follow-up with administrative health claims and employee surveys

Primary outcome

Healthcare expenditures; health behaviors (exercise, smoking, sleep); clinical health outcomes (BMI, blood pressure); absenteeism; job performance ratings; job tenure

Effect estimate

Healthcare spending: no significant difference (p>0.05 across all 38 outcomes pre-specified). Exercise: significantly higher self-reported exercise in treatment group. Weight, blood pressure, cholesterol, smoking: no significant difference. Absenteeism: no significant difference. Job performance: no significant difference. Tenure: no significant difference. The one positive finding — exercise — did not translate to any measurable health outcome.

Decision

Results published in the QJE generated significant industry debate; RAND Corporation prior analyses of wellness programs also found null or very small effects on medical costs; the $50B employer wellness industry faced growing scrutiny; some employers shifted focus from population-wide wellness programs to targeted disease management; the evidence has not substantially reduced employer investment in wellness programs, which remain popular as employee benefits even in the absence of demonstrated health ROI

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Result

Null

Evidence strength

Strong

Randomized trial, replicated across multiple sites or studies.

Replication status

Replicated

Institution

University of Illinois / Harvard / National Bureau of Economic Research

Location

University of Illinois, USA

Year

2016

Policy area

Public Health

Mechanism

Human capital