Discriminant Analysis: Issues and Problems

Introduction

It was in the mid 1930s when Sir Ronald A. Fisher (1890–1962) formally introduced the notion of “discriminant analysis” (DA) in writing. His introduction involved prediction of group membership in a two-group context – a predictive discriminant analysis (PDA). The notion of “discriminant analysis” became of interest to researchers in various areas of study in the 1950s and 1960s (e.g., Cooley and Lohnes 1962). That is when the variant which may be termed “descriptive discriminant analysis” (DDA) “caught on.”

PDA Versus DDA

The mixing of PDA and DDA is fairly common in many books and journal articles. The distinction of PDA from DDA is, to the current writer, fairly important for description, interpretation, and reporting purposes. A PDA is used to determine a “rule” for predicting membership in one of k groups of analysis units based on measures on p predictor variables. The rule, then, consists of k composites of the ppredictors. These composites may be of linear form...