A set of questions in a research study in which the participant’s preferences among a set of several possible choices (for example, products, ads, features, candidates) are gauged by asking them their preferences among several pairs of the possible choices, one at time. For example, to determine a participant’s preference among five ads, labeled A, B, C, D, and E, the research participant would be asked whether they prefer A or B, C or D, A or D, C or E, etc.