First, 12,459 benefits-eligible university employees were invited to complete a 15-minute online survey about health and wellness. Roughly 4,800 bothered to fill out the survey, at which point they were randomly divided into seven groups. Six of the groups were offered varying levels of incentives to participate in a new wellness program. “Those who successfully completed the entire program earned rewards ranging from $50 to $350,” the researchers noted, “with the amounts randomly assigned and communicated at the start of the program.” Members of the seventh group were told they might be contacted for future surveys and were otherwise left alone.
After the program had run its course, the researchers — Damon Jones, David Molitor and Julian Reif — compared the people who were offered the wellness program with the people who were left alone. Thirty-nine wellness-related outcomes were measured, from sick days to health-care spending. The researchers found no significant effect in 37 of the 39 outcomes. The two variables that showed “significance” weren’t actually all that significant: One was “an increase in the number of employees who ever received a health screening,” the paper reports, and the other “an increase in the number who believe that management places a priority on health and safety.”
The result from Illinois contrasts sharply with some of the earlier literature on these sorts of programs. A 2010 meta-analysis published in Health Affairs found that medical costs fell by $3.27 for every dollar spent on wellness programs, while the cost of absenteeism declined by $2.73.
But that earlier literature was vulnerable to a problem known as selection bias: The companies that offer wellness programs, and the employees who use them, might not be representative of the population as a whole.
For example, thanks to the Bureau of Labor Statistics, we know that higher-wage employees are more likely to be offered a wellness program at work. And thanks to decades of social-science research, we also know that people with higher incomes tend to be healthier. This is true even when they use precisely the same health care as those who don’t earn as much: The famous Whitehall Studies of British civil servants from the 1960s to the 1980s found that senior bureaucrats fared much better than those in the lower tiers, even though they were all covered by Britain’s National Health Service.
There can also be selection effects between those obnoxiously fit folks who leap at the opportunity to fine-tune their health and those who are too sick, or uninterested, to participate. That’s what the Illinois study found: Average annual medical spending for those who didn’t participate in the wellness program was about $1,400 higher than for people who participated, even before they joined.
Which is exactly why the study needed to be designed as a randomized experiment. If you look at the results of wellness programs without controlling for the types of people who use them, it can seem as though they’re making people healthier when they’re just scooping up healthy employees and running them through useless hoops. Companies might even see real benefits in terms of health-care costs — but only because the incentives offered for wellness-program participation make their workplaces more attractive for healthy people than sick ones.
If selection bias really is driving the apparent benefits, then the incentives often offered for participation essentially redistribute wealth and resources upward, from the sick to the healthy and, by extension, from lower-earners to the more affluent. Government policies encouraging wellness programs should be discontinued. But even without government help, companies might well decide it is in their interest to keep them going. Decades of government policy have given employers a substantial financial interest in your health, between your health insurance, your workers’-compensation premiums and the liability problems that sick employees can create.
That’s not to say employers are cynically using these programs to discriminate against the unhealthy. Selection bias is insidiously seductive that way: It can make useless or even counterproductive interventions look as if they’re working spectacularly.
But it does mean that no matter what future research shows, employers will probably find reasons to keep these programs going. Because even if they don’t produce any actual wellness, they might still be very healthy for the bottom line.