Methodology: Statistical methods are used in each phase of KE. In this work; we focus our attention on the choice of experimental design for the synthesis phase and on the analysis methods for the model building. In particular; we compare the KE results by using classical fractionated designs; with the efficiency of saturated designs and supersaturated designs. Two methods of analysis are tested: categorical regression analysis (CATReg) and Ordinal Logistic regression (OLR). Moreover; a comparison between the results of ranking and rating procedures are discussed for the saturated design.
Findings: The comparison among the suggested statistical methods is performed through a study on railway seats design in a virtual reality environment. The results of the analysis support the use of Fractional Factorial Design instead of saturated and supersaturated design. The two methods of data analysis give the same results. No evident differences emerge from the comparison of rating and ranking procedures.
Value of paper: This paper propose optimal experimental design selection strategies to reduce the number of product concepts to design; test and evaluate; and data collection analysis strategies in order to improve the appropriateness and the robustness of model building phase at the end of the synthesis phase. If applied faster and more reliable; a KE approach can overcome the distrust of industrial designers toward the methods belong to the emotional design area.
Keywords: Kansei Engineering; Saturated Design; Nested Experimental Design; Ordinal Logistic Regression; Categorical Regression