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A tale of 3 scales: How do the 9-pt, Labeled Affective Magnitude, and unstructured Visual Analog scales differentiate real product sets of fresh berries?

Henry F. Yeung, Kumpol Homwongpanich, Elizabeth Michniuk, Dominic Rovai, Massimo Migliore, Amy Lammert, Jacob Lahne
Food quality and preference 2021 v.88 pp. 104109
blackberries, blueberries, food quality, hedonic scales, industry, scientists, strawberries
Selection of scales for measuring liking remains an active area of discussion in sensory science, but there is still no real consensus on which scale a sensory scientist working in industry should use to measure actual hedonic responses to food products. Key criteria for a hedonic scale are whether it sensitively and efficiently discriminates among consumer responses to products. Therefore, the key question this study investigates is whether the use of different scales by the same subjects on the same products in a real-world situation would provide different results for the sensory analyst. To address this question, this study comprises the evaluation of 6 for-market varieties each of 4 berries—raspberry, strawberry, blackberry, and blueberry—by the same N = 147 untrained subjects using 3 popular scales—the 9-pt hedonic scale, the Labeled Affective Magnitude Scale (LAM), and the unstructured Visual Analog Scale (VAS). Data were analyzed by mixed-effects ANOVA with subsequent scale-performance and post-hoc measures, and by bootstrapping simulation studies to estimate the empirical power of each scale to detect differences. For each berry type, significant differences in liking were detected by at least one scale, but scale performance differed. The 9-pt scale was the only one of the three to detect differences among the blueberry samples, and examination of ANOVA and post-hoc results for all berries showed that the 9-pt scale consistently discriminated among samples as well or better than the other two scales. In simulation studies, the 9-pt scale showed reliable detection of differences at sample sizes smaller or equal to the other two scales. It is apparent that—in terms of real-world applications and expected detection of differences—the 9-pt scale discriminates consumer liking for different products as well or better than two continuous scales and can be retained in industry research programs.