Similarity-to-Ideal and Degree-of-Difference: A new consumer test
We present a procedure designed to provide both preference and difference results in a consumer test. Two sample types (A, B) are evaluated in duplicate via an all-permutations 2-present-4 design. Evaluation occurs on an unstructured line scale anchored at Same (left) and Different (right). Bite 1 is evaluated via Similarity-to-Ideal, proximity to Ideal implying preference, with samples served in sequential monadic in design order. Same=100 and Different=0, but values are hidden from assessors. Consumers reserve second bites of each sample for a Degree-of-Difference (DoD) evaluation in which the first sample presented becomes the Reference sample (REF). Same=0 and Different=100, again hidden from assessors. A and B are REF in equal proportions, and the DoD test involves one Same Pair (AA or BB) and two Different Pairs (AB, AB or BA, BA).
Evaluation is on the same scale, but referring to REF. Of interest is the difference in gap between the Same Pair and the Different Pair.
Consumers (n=100) evaluated 2 types of commercial crackers (Control, Test) using the procedure. After a delay, consumers repeated the procedure with 2 types of commercial cookies (Control, Test). In each case, there was a slight formulation change. Results are given in Fig. 1 (see the online version). Cracker data shows no significant difference between Control and Test for Similarity-to-Ideal, whether using a linear mixed effects model or a nonparametric analysis of ranks; the DoD results indicate a slight but statistically significant difference between the Same Pair and the Different Pairs. Conclusions were similar for cookies. Thus, in each case, the consumer panel discriminated a slight difference between Control and Test, but no difference was observed in implied consumer preference. Further investigation is required to compare results from the procedure with conventional hedonic and sensory discrimination test results.
Castura, J. C., King, S. K, & Findlay, C. J. (2015). Similarity-to-Ideal and Degree-of-Difference: A new consumer test. In: 11th Pangborn Sensory Science Symposium. 23-27 August. Gothenburg, Sweden.