Sensitivity comparison of sequential monadic and side-by-side presentation protocols in affective consumer testing.

The relative sensitivity of side-by-side and sequential monadic consumer liking protocols was compared. In the side-by-side evaluation, all samples were presented at once and evaluated together 1 characteristic at a time. In the sequential monadic evaluation, 1 sample was presented and evaluated on all characteristics, then returned before panelists received and evaluated another sample. Evaluations were conducted on orange juice, frankfurters, canned chili, potato chips, and applesauce. Five commercial brands, having a broad quality range, were selected as samples for each product category to assure a wide array of consumer liking scores. Without their knowledge, panelists rated the same 5 retail brands by 1 protocol and then 3 wk later by the other protocol. For 3 of the products, both protocols yielded the same order of overall liking. Slight differences in order of overall liking for the other 2 products were not significant. Of the 50 pairwise overall liking comparisons, 44 were in agreement. The different results obtained by the 2 protocols in order of liking and significance of paired comparisons were due to the experimental variation and differences in sensitivity. Hedonic liking scores were subjected to statistical power analyses and used to calculate minimum number of panelists required to achieve varying degrees of sensitivity when using side-by-side and sequential monadic protocols. In most cases, the side-by-side protocol was more sensitive, thus providing the same information with fewer panelists. Side-by-side protocol was less sensitive in cases where sensory fatigue was a factor.