Restricted unfolding: Preference analysis with optimal transformations of preferences and attributes

The fundamentals of preference mapping are revisited in the context of a new restricted unfolding method that has potential for wide application to product optimisation for consumers. Since more of an attribute is not necessarily preferred, the unfolding distance model provides estimates of ideal points for consumers and therefore provides a more adequate representation of the preference relationships, compared to conventional internal preference mapping. Compared to other ideal point methods, the new unfolding technique offers advantages in terms of allowing for the ordinal nature of the ratings, rather than implicitly assuming that ratings are linear. The proposed restricted unfolding model incorporates property fitting, both passive, as a separate, second step, and active, as a restriction on the product locations. This is also available as a restriction on the respondents’ locations and as such establishing a link between internal and external preference mapping.