• Workplace Wellness Programs Don’t Work Well. Why Some Studies Show Otherwise.

    The following originally appeared on The Upshot (copyright 2018, The New York Times Company).

    The gold standard of medical research, the randomized controlled trial, has been taking a bit of a beating lately.

    An entire issue of the journal Social Science and Medicine was recently devoted to it, with many articles pointing to shortcomings. Others have argued that randomized controlled trials often can’t address the questions that patients and physicians most want answered. I recently wrote about the limitations of the method in studying effectiveness, which is what we care about in real-world situations.

    But the randomized controlled trial remains a powerful tool. It’s still, perhaps, the best method for conducting explanatory research. In past articles, I have recounted numerous times when hypotheses from observational studies, those based solely on observations of particular groups, have failed to be confirmed by a controlled trial.

    Perhaps the greatest strength of the randomized controlled trial is in combating what’s known as selection bias. That occurs when groups being studied (intervention and control) are already significantly different after they are “selected” to be in the intervention or not. One of the most elegant examples of why we need such trials came recently in an examination of employer-sponsored wellness programs.

    These programs are usually offered by employers to make their employees healthier. They can offer screening for a variety of reversible conditions; access to weight-loss programs or gyms; encouragement and support; and sometimes even chronic disease management. Many of the analyses of these programs have shown positive results.

    Almost all of those analyses are observational, though. They look at programs in a company and compare people who participate with those who don’t. When those who participate do better, we tend to think that wellness programs are associated with better outcomes. Some of us start to believe they’re causing better outcomes.

    The most common concern with such studies is that those who participate are different from those who don’t in ways unrelated to the program itself. Maybe those people participating were already healthier. Maybe they were richer, or didn’t drink too much, or were younger. All of these things could bias the study in some way.

    The best of these observational studies try to control for these variables. Even so, we can never be sure that there aren’t unmeasured factors, known as confounders, that are changing the results.

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