When should we trust the evidence and the experts who interpret it for us?

A new study makes headlines. It shows a diet works, a supplement sharpens memory, a teaching method transforms reading scores or a management practice improves team productivity. So we adjust how we eat, parent or work. We follow the science.

A few months later, another headline overturns the first. Eggs were bad for us, then good again. Red wine protects your heart, or does it? Dark chocolate, low-fat diets, standing desks, masks during a pandemic: Recommendations based on the science keep changing. Eventually, people stop trusting what “studies show.”

But that is how science works: Evidence accumulates; early results get tested and some hold up, others don’t. The problem is that we report and act on evolving evidence as if it is final.

In a new article, I argue that this tendency to treat preliminary results as if they were conclusive leads to overconfident policy claims and contributes to the declining trust in science. I offer a new framework to help policymakers classify evidence maturity.

The insights can guide all of us to interpret scientific evidence in our daily lives.