Measuring Simple Preferences: An Approach to Blind, Forced Choice Product Testing

When comparing alternate product formulations, or evaluating competitors' formulations, researchers often conduct blind, forced choice product tests. In this study, the authors present an approach to designing these tests and evaluating their results. Two types of tests are considered: repeat paired comparisons formats, and formats consisting of several triangle tests and a single paired comparison. The approach consists of psychophysical assumptions, discrimination and preference constructs, and a set of analytical techniques. Using this approach, a researcher can compare product test formats to see which one most efficiently estimates a given construct of interest. The approach can also be used to gauge sample size requirements for a particular product test format and to estimate confidence intervals for an observed product test result. To illustrate the approach the authors compare two popular product test formats—the Four Paired Comparisons, and the Double Triangle Single Preference.