Dr. Martha Perez examines Maria Lebron in a room at the Community Health of South Florida, Doris Ison Health Center on February 21, 2013 in Miami, Florida. (Joe Raedle/GETTY IMAGES)

Retailer CVS was in the news Tuesday for requiring that all of its 200,000 employees who participate in the company’s health-insurance plan get a health screening (paid for by CVS) that assesses their weight, height, body fat and cholesterol levels-or pay some $600 more for their health coverage a year. The Boston Herald, followed by publications including the Los Angeles Times and Gawker, reported that if employees do not submit to the health assessment by May 1 then their annual health insurance costs will increase.

The interest in the story is understandable. Critics worry that the request could be invasive, even though CVS has been clear that a third-party administrator would be reviewing the data and would not share it with the company. No matter how private the information may be, sharing weight and other health details can feel a little unnerving.

Yet I’m actually surprised there’s as much interest in the news as there seems to be. CVS is hardly the first company to make such a request: According to human resources consultancy Aon Hewitt, 83 percent of respondents to a 2013 survey of more than 1,000 U.S. employers said they offer some type of incentive to employees for taking a health-risk questionnaire or submitting to a biometric screening. Other companies even go much further, asking employees not only to submit to a health-care screening but to actually meet certain blood pressure or cholesterol thresholds, or at least agree to work toward improving them, to receive the discount.

The real question to me, however, is not whether employers should ask workers to submit to a health screening, it’s how they should motivate them to do it. According to the data from Aon Hewitt, 79 percent of those employers who use financial incentives give rewards for screenings, whereas only 5 percent dole out penalties. (The rest use some combination of both.)

That could be changing, though. Stephanie Pronk, a senior vice president in the consultancy’s health and benefits practice, said in a phone interview that some 50 percent of the survey’s respondents said they would strongly consider switching to penalties in the next three to five years. “The general philosophy has been you tend to want to reward people for those behaviors,” Cronk says. “But there’s also a very strong body of literature that says [penalty] has a greater impact.” She emphasizes that because the literature is split on what works better-the carrot or the stick-leaders need to decide what works best for their specific organization’s culture.

For CVS, the answer appears to be the stick. In the past, the company rewarded employees with a discount for participating in a health screening, but it has since decided to charge those who don’t comply in order to “accelerate the participation of the employee base,” says Carolyn Castel, CVS’s vice president of corporate communications. And what do employees think of the change? “Anything we say would be strictly anecdotal,” Castel says.

Who knows how employees will respond. Asking non-participants to pay more or giving a benefit to those who sign up is, in a sense, the same thing: In either case, the employee who doesn’t take the health assessment ends up paying more than the employee who does. But while one approach sends a message that’s encouraging and positive, the other can feel punishing — however much the program may be “voluntary.” How that plays out in a company’s culture is hard to measure, but there are risks. Anytime leaders decide to forego the carrot for the stick, whether to boost employees’ job performance or to improve their body mass index, a lot more needs to be weighed than just the cost to the bottom line.