Are Testimonials Trustworthy Evidence? Does one middle-aged woman’s positive experience with Skin’s Shangri La—“I’m nearly 60, but no one believes it”—provide evidence that this moisturizer makes for younger-looking skin? Testimonials use a volunteer sample of one person, usually a biased person; moreover, you can bet that the testimonial a company uses in its advertising is the most flattering one.
Susan Nolan