Statistics for all: Replication (why you should have been suspicious of power-posing from the start)

I’ve got a free, low-tech life hack for you that will save significant time and money — and maybe even improve your health. All you need to do is one little thing. Before you let the latest research results change your behavior, check to see if the research has been replicated!

One of the hallmarks of modern science is the notion that one study of a new phenomenon — especially a single small study — proves nothing. Most of the time, the results of such studies can do little more than suggest possibilities. To arrive at proof, results have to be replicated — again and again, usually in a variety of contexts. This is important, especially in the social sciences, where phenomena are difficult to measure and the results of many new studies cannot be replicated.

Researchers used to be trained to avoid even implying that findings from a new study were proven facts. But when Amy Cuddy set out to share the results of her and her colleagues’ power-posing research, she didn’t simply imply that her results could be generalized. She unabashedly announced to an enthralled Ted Talk audience that she’d discovered a “Free, no-tech life hack…that could significantly change how your life unfolds.”

Thanks to this talk, many thousands — perhaps millions — of people-hours have been spent power-posing. But it’s not the power-posers whose lives have changed. Unfortunately, as it turns out, it’s Dr. Cuddy’s life that changed significantly — when other researchers were unable to replicate her results. In fact, because she had made such strong unwarranted claims, Dr. Cuddy became the focus of severe criticism.

Although she was singled out, Dr. Cuddy is far from alone. She’s got lots of company. Many fads have begun just like Power Posing did. Here’s how it goes: A single small study produces results that have “novelty appeal,” the Today Show picks up the story, and thousands jump on the bandwagon! Sometimes, as in the case of power-posing, the negative impact is no worse than a bit of wasted time. But in other cases, such as when our heath or pocketbooks are at stake, the impacts can be much greater.

“But it worked for me!” If you tried power-posing and believe it was responsible for your success in achieving an important goal, you may be right. The scientific method isn’t perfect — especially in the social sciences — and future studies with better designs may support your belief. However, I recommend caution in relying on personal experience. Humans have powerful built-in mental biases that lead us to conclude that positive outcomes are caused by something we did to induce them. This makes it very difficult for us to distinguish between coincidence and cause. And it’s one reason we need the scientific method, which is designed to help us reduce the impact of these biases.

Replication matters in assessment development, too

Over the last couple of decades, I’ve looked at the reliability & validity evidence for many assessments. The best assessment developers set a pretty high replication standard, conducting several validity & reliability studies for each assessment they offer. But many assessment providers—especially those serving businesses—are much more lax. In fact, many can point to only a single study of reliability and validity. To make matters worse, in some cases, that study has not been peer reviewed.

Be wary of assessments that aren’t backed by several studies of reliability and validity.

My organization, Lectica, Inc., is a 501(c)3 nonprofit corporation. Part of our mission is to share what we learn with the world. One of the things we’ve learned is that many assessment buyers don’t seem to know enough about statistics to make the best choices. The Statistics for all series is designed to provide assessment buyers with the knowledge they need most to become better assessment shoppers.