Beyond usability: designing for consumers' product experience using the Rasch model

Many manufacturers wish to relate the physical properties of their products to customers' affective responses so that they can improve the design of their products. Rasch measurement theory is a novel approach in this context that could offer business benefits over other approaches. The aim of the research was to determine whether Rasch measurement theory can support the construction of a scale to measure the affective impression of a moisturiser cream elicited by the compliance of the moisturiser's packaging. The compliances of packaging used to develop a scale for the impression of the contents of the packaging in previous research were measured. New packaging prototypes were manufactured with a range of compliances to determine whether affective responses to them could be predicted. A new sample of 67 participants rated the prototypes against Likert statements on a five-point scale. The statements were derived from descriptions of the users' product experience. The scale was recalibrated using a multi-facet Rasch model. It was found that the affective responses to the prototypes fell within the range predicted by the original scale. The results demonstrate that Rasch measurement theory can be used to achieve the objective correspondence between affective responses and the physical properties of a product, and the information can be used in new product development.