A Note on Huberty and Wisenbaker’s “Views of Variable Importance”

Abstract

This article investigates criteria for assessing variable importance in MANOVA and descriptive discriminant analysis. Two criteria suggested by Huberty and Wisenbaker (1992) are examined, namely, (a) contribution to linear discriminant function scores and (b) contribution to grouping variable effects. Thomas and Zumbo (1996) have shown that the first criterion can be operationalized using discriminant ratio coefficients (DRCs). It is shown in this article that DRCs also provide an operational definition of grouping variable effects. Thus, it is proposed that the two criteria be amalgamated and called the contribution to grouping effects and discriminant scores. The F-to-remove indexes used by Huberty and Wisenbaker can then be regarded as operational definitions of a separate criterion, namely, the amount of additional information contributed to group discrimination.