In the degree of difference methodology (DOD), subjects are presented with pairs of samples, either identical or different, and must indicate how different the samples are using a t-point category rating scale. In this article, the Thurstonian model for the DOD assuming independent assessments is derived. The model permits the estimation of the size of the underlying difference between the products (delta), the variance of this estimate, as well as the sizes of the t-1 tau criteria (scale boundaries on the difference perceptual distribution). This model expands further the collection of Thurstonian models already available for many discrimination, rating and ranking methodologies.
Ennis, D. and Rousseau, B. (2015). A Thurstonian model for the degree of difference protocol. Food Quality and Preference, 41, 159-162.
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A Thurstonian model for the degree of difference protocol
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