On a recent trip to Lincoln, NE, I visited Lincoln Industries, a company that makes chrome trims for Harley-Davidson motorcycles. I was curious about the firm’s award-winning wellness program, especially since more employers are penalizing workers by making them pay more for their health insurance if they fail to meet certain health goals.

At the heart of Lincoln Industries’ wellness program is its Platinum Scorecard, which awards points to workers who achieve good results on several markers of health such as blood pressure, cholesterol, tobacco use, waist circumference and blood sugar levels. For example, if waist circumference for men is less than 40 inches and for women less than 35 inches, they earn one point. If they don’t smoke, they get three points.

Apparently it’s not easy to score between eight and ten points, but those who do get an all-expense paid trip to climb a mountain in the Rockies. This year, 200 employees out of a workforce of 510 qualified to climb 14,000 ft. Mt. Elbert in Colorado.

High scorers also pay less for company-sponsored insurance. Workers who don’t participate or who score three points or less pay the standard premium, which this year is $6,744. Those who score more than seven points pay nearly $2,700 less — a hefty discount meant to encourage better life-style health behaviors.

Most companies offer these programs to save on health insurance and other health-related costs, such as absenteeism and productivity. At Lincoln Industries, company officials told me this year the firm hopes to save two dollars for every one dollar it spends on its wellness activities, which include a gym and an onsite clinic. Workers who are sick can stop in at the clinic rather than lose a half of a work day sitting in a doctor’s office.

It’s quite possible Lincoln Industries will meet its goal. But despite individual success stories and rewards to climb mountains, the data show that wellness programs don’t deliver the dramatic savings that sellers of these wellness packages promise. The latest evidence comes from RAND Corp., which studied such programs under a contract from the U.S. Departments of Labor and Health and Human Services.

RAND researchers said that when they compared program participants to nonparticipants, they found “statistically significant and clinically meaningful improvements in exercise frequency, smoking behavior, and weight control, but not cholesterol control.” RAND, however, noted no “statistically significant decreases in cost and use of emergency department and hospital care” but noted that over time there’s reason to believe direct medical costs would come down if employees stayed with these program.

Motivation seems to be the key. RAND researchers found that participation in these programs is not great. Fewer than half of all employees undergo initial screening, and of those identified for needing intervention, less than one-fifth choose to participate.

We’ve known for a long time that evidence for the effectiveness of wellness programs is limited or lacking. A review of the literature by the California Health Benefits Review Program, which advises the California legislature about health insurance mandates, found, for example, that the preponderance of evidence from randomized controlled trials suggests wellness programs do not lower blood pressure, blood sugar, or cholesterol (risk factors for disease). The California review also found that randomized controlled trials have shown that participating in smoking cessation programs increases the chances people will quit.

What’s the evidence for making workers who fail to achieve certain targets pay higher insurance premiums? The California review identified no randomized controlled trials that examined the impact of premiums and cost sharing for health insurance linked to participation in workplace wellness programs. In other words, it’s not really clear the carrot and stick approach works in the workplace.

So why do such programs persist? RAND observed that employers are probably unaware of the academic literature, possibly because they are not evaluating their own programs. Perhaps, though, there’s another reason. There may be intangibles that can’t be measured. Says Greg Howe, Lincoln Industries’ wellness manager: “A lot of blue collar Nebraska workers have never been out of the state. They’ve never taken a vacation in their life. A day later they are standing on top of a mountain. They’ve accomplished something they’ve never dreamed of.”

Trudy Lieberman is a journalist and an adjunct associate professor of public health, Hunter College. She blogs regularly on the Prepared Patient blog.