Preprint No. A-00-16

Heiko Großmann, Ulrike Graßhoff, Heinz Holling, Rainer Schwabe

Optimal Designs for Paired Comparisons in Main Effects Analysis of Variance Models

Abstract: In psychological research paired comparisons which demand judges to evaluate the trade-off between two alternatives have been shown to yield valid estimates of the judges' preferences. For this situation we present optimal designs in a discrete setting where the alternatives are modeled by an analysis of variance model with main effects only. While product type designs are theoretically optimal they bear the disadvantage of exponentially increasing sample sizes. We employ orthogonality and combinatorial tools like Hadamard matrices to achieve optimal designs which are saturated or which have sufficiently small sample sizes increasing linearly in the number of factors involved. Moreover, optimal designs are constructed when the number of varying factors is restricted for each pair of alternatives.

Keywords: paired comparisons, main effects model, optimal design, equivalence theorem, symmetrization, additive model, marginal design, product design, Hadamard matrix, orthogonal array, saturated design, profile strength

Language: ENG

Available: Pr-A-00-16.ps

Contact: Schwabe, Rainer, Freie Universität Berlin, Fachbereich Mathematik und Informatik, Arnimallee 2-6, D-14195 Berlin, Germany (schwabe@math.fu-berlin.de)

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