GENFOLD2: A General Unfolding Methodology for the Analysis of Preference/Dominance Data

This paper is a brief description of the GENFOLD2 methodology which is a set of multidimensional unfolding models and algorithms for the analysis of preference or dominance data (cf. DeSarbo & Rao, 1984, 1986). GENFOLD2 allows one to perform internal or external analyses, constrained or unconstrained analyses, conditional or unconditional analyses, metric or nonmetric analyses, as well as providing the flexibility of specifying and/or testing a variety of different types of unfolding-type preference models including simple, weighted, and general unfolding analysis. An alternating least-squares algorithm is utilized in the estimation of the specified parameters. The methodology is illustrated in this paper with a set of preference data for over-the-counter pain relievers. Some future research directions are also identified.