Robust Dual Scaling with Tukey's Biweight

Abstract

Use of the method of reciprocal biweighted means (MBM) for dealing with the outlier problem in dual scal ing compared favorably with other robust estimation procedures, such as the method of trimmed reciprocal averages (MTA). Like the MTA, the MBM was easy to implement and it converged to a stable point when a two-step estimation procedure was used. One advantage of the MBM over the MTA was that it afforded greater control in fine tuning the final solution. Empirical re sults for four datasets, some containing multiple outli ers, are presented. Index terms: biweight, dual scaling, outliers, reciprocal averages, robust estimation, Tukey 's biweight.