Rejoinder to “The Variety of an Assortment: An Extension to the Attribute-Based Approach”

Abstract

Variety Perceptions Redux We comment on the paper by van Herpen and Pieters (2002, hereafter HP) and relate it to our earlier paper in this journal (Hoch, Bradlow, and Wansink 1999, hereafter HBW). The basic premise of HP is that people can engage in either a product or attribute-based approach when making variety perceptions. When people adopt a product approach they compare the products in an assortment on a pairwise basis and perceived variety is a function of dissimilarity or psychological distance between the pairs. When following an attribute approach, people engage in a bottom-up process where they focus on the entropy of the individual attributes and pairwise covariation between attributes. Young and Wasserman (2001) have shown that both people and pigeons rely on entropy when making variability discrimination judgments. HP suggest that the distinction between product versus attribute approaches to variety perception is similar in spirit to brand versus attribute processing in multiattribute choice (Bettman et al. 1998). Although we appreciate this conceptual distinction, we show that the two approaches are very similar mathematically. After appropriately standardizing our pairwise distance measures to control for differences in assortment size, we find that due to high collinearity, it is not possible to distinguish one approach from the other both in our (HBW) data and the data of HP. Finally, even though entropy and lambda are generally informative summary statistics, a couple of features render them less appropriate in some situations than others.