Marketers need to find a balance between advertising a product’s strengths and overpromising what it can deliver. Some research has found that the optimal number of claims to make about a product is three. For example, an advertisement could claim that a shampoo makes hair cleaner, stronger and fuller—but the advertisement shouldn’t lengthen that list to include softer, shinier, and other attributes as well. Attaching more than three promises to a product may make consumers more skeptical.