Drivers of Liking® with Incomplete Block Designs
Ennis, D. M. and Rousseau, R. (2022). IFPress, 25(2) 3-4.
Incomplete block (IB) designs were originally constructed to improve precision in agricultural experiments by limiting exposure to variability within blocks and thus improve the reliability of treatment comparisons. Their use in product testing arises from the practical fact that respondents (blocks) sometimes cannot (or should not) be exposed to the full set of products to be tested. IB designs provide a convenient approach to setting up incomplete sets of products to be tested by individuals and analyzed using Landscape Segmentation Analysis® (LSA). LSA assumes that a liking response depends on a combination of past and present experience. The method, called unfolding, provides the basis for identifying individual ideal and item points in a low-dimensional space of hedonic drivers. Typically, in consumer product categories, the drivers of liking space is two- or three-dimensional. Figure 1 displays the concept of unfolding through the action of unfolding a fan. In the folded, or barely unfolded, state a fan displays images that later may appear in different parts of the space. Inspecting the fan in the folded state provides very little information about the complex images that unfolding will generate. Images of the same color seen on the folded fan may appear surprisingly different and in different locations when the fan is unfolded.