Phương pháp sản phẩm lý tưởng: So sánh giữa kỹ thuật cho điểm và xếp hạng
Ideal profile method (IPM) has been proved to be an effective and useful method in product development. This method is similar to QDA® except that the samples are not rated by trained panelists but naïve consumers. However, the rating technique is often found to be difficult for consumers. This study proposed a new variant of IPM using ranking technique to facilitate the data collecting by naïve consumers. The samples were five commercial lemon green teas available in Vietnam market. The participants were bottled tea consumers who were randomly assigned into two groups of 60. The first group performed the conventional IPM (aka “IPMQDA”) using rating technique, in which the samples were presented in randomized monadic order and the participants rated both the perceived and ideal intensities of the attributes on the 10-cm line scales. The second group, on the other hand, performed the new variant of IPM (aka “IPM-RDA”) using ranking technique, in which the participants ranked the whole set of the products (ties allowed) for each attribute at the same time. An empty cup representing the ideal sample was then inserted into the ranked set of products at the most suitable position depending on the ideal intensity. The result showed that two product spaces were highly similar. However, compared to IPM-QDA, IPM-RDA better improved the discriminability, increased the consensus among the assessors and reduced the variability of ideal profile. These findings indicated that ranking was more efficient than rating in gathering descriptive data using naïve consumers.