Every survey, no matter how well designed, is subject to influences beyond the questions themselves. One unavoidable influence is human nature. People may make assumptions, act on preexisting beliefs, fail to pay attention, and engage in other behaviors that affect their responses to a survey.1 For example, if a survey shows an image of an athletic shoe and asks which company makes the shoe, some consumers might say “Nike” simply because they know that Nike makes athletic shoes, regardless of any logo, shape, color, design, or other characteristics of the shoe in the survey. If ignored, this type of “noise” in the data makes it less reliable because irrelevant responses are included.
Survey controls exist to address this problem. A control in a survey is like a placebo in medical research: it uses a false image, phrase, question, or answer option to detect survey noise. Respondents may provide answers that appear confused or misleading, but if the disputed feature is not actually
