Assessing Main Effects in Interactive Regression Models
Year
1988
Author(s)
Youjae Yi
Journal
American Marketing Association Educators' Conference Proceedings
Pages
1-21
This paper investigates the problems in accessing main effects of interval scaled variables in interactive regression models. Inclusion of an interactive team induces the following problems in assessing main effects; 1) conclusion can change dramatically from "strong" to "no" main effects with allowable scale transformations, 2) severe multicollinearity is introduced, and 3) the interpretation of main effects is ambiguous. It is shown how a mean-centering procedure reduces these problems, and these issues are illustrated with an empirical example.