Are wellness programs effective?

That’s one of many questions being asked by employers considering implementing a program. The answer depends. What’s “effective”? Is it decreased medical costs, increased employee productivity, reduced absenteeism?

Various studies have reached a range of conclusions, all dependent on the researcher’s definition of “effective.”

Now, the National Bureau of Economic Research is weighing in with their answer: No.

Related: 4 wellness lessons from University of Louisville's "Get Healthy Now" program

NBER created and implemented a wellness program for one company’s more than 12,000 employees at the University of Illinois at Urbana-Champaign and found no noticeable improvement in health behaviors, medical expenditures, employee productivity and other such measures after one year.

What NBER did find: the 56 percent of employees that did elect to participate in the wellness program showed lower medical expenditures and healthier behaviors in the year prior to the program than non-participants, suggesting that they already had some degree of health-consciousness.

The program, iThrive, offered incentives, including a $30 Amazon gift card for completion of a 15-minute baseline health survey. Respondents were then divided into one of five test groups or a sixth control group. Further testing included biometric screening and health risk assessment, followed by an invitation to participate in wellness activities throughout the year. Monetary rewards ranged from $50 to $350, depending on the treatment group.

At best, NBER concludes, wellness programs can be used as a screening tool, used as an incentive by employers to recruit or retain employees who are likely to be lower-cost health care users.

NBER’s conclusion won’t be the last we hear about wellness programs, of course. Previous studies have emphasized the increasing returns of programs as they continue over time. "Most studies report break-even returns or better after two or more years of program implementation, and several studies suggest a $3 return for every $1 invested in the program after three-and-a-half years,” Hans Hage, vice president of product development for StayWell, told BenefitsPro last year.