The FTC recently announced a settlement over advertising claims for dog food. Why should supplement makers care? One: you might sell pet supplements. Two: the FTC’s argument why the claims fail is one that it makes in many cases involving health-related claims for humans.
The dog food maker had claimed that a study it conducted showed that, with its dog food and proper care, dogs were able to live longer than their breed’s typical lifespan. The dog food maker also claimed that several specific dogs in the study lived 30% longer. The FTC alleged that these claims were misleading given that the dog food maker’s evidence “consisted primarily of results from a single study,” and those results “showed no significant difference in the median age at death of dogs in the study relative to the typical age at death of dogs of the same breed.” The FTC, in effect, argued that, where the “typical age at death” is acting as the control, there was no between-group statistical significance.
Regardless of what’s being tested, the FTC often argues that there should be between-group statistical significance in order for the testing to be considered reliable. In its guidance on dietary supplement advertising, the FTC states, “Statistical significance of findings is  important. A study that fails to show a statistically significant difference between test and control group may indicate that the measured effects are merely the result of placebo effect or chance.”