Comparison Conditions in Research on Persuasive Message Effects: Aligning Evidence and Claims About Persuasiveness

In persuasion message effects research, two kinds of research design are common. One compares the persuasiveness of two different advocacy messages on the same topic. The other compares the persuasiveness of an advocacy message against a no-advocacy-message control condition. Because these two designs contain different comparisons they underwrite different claims, but the designs–and their corresponding claims–are prone to misunderstanding and confusion. And when a study combines the two designs, especially complex issues can arise. This article aims to sort out the relevant issues in the service of better alignment between evidence and claims in persuasive message effects research.