Evaluating quality measured on a ternary ordinal scale

Abstract

This paper deals with the evaluation of process/product quality measured via a ternary ordinal scale. Recently, a new approach for dealing with ordinal quality variables, based on constructing a quality ladder using rank and dispersion criterion, was proposed. In this method the quality of a given sample is characterized by its relative position on the constructed quality ladder. The present paper proposes a new mechanism for constructing such a quality ladder. This method is called proportion ratio and dispersion (PR&D). The underlying logic, advantage and applications of the proposed method are discussed and demonstrated using software developed by the authors. Copyright © 2008 John Wiley & Sons, Ltd.