Interaction Effects: Centering, Variance Inflation Factor, and Interpretation Issues

Abstract

Research hypotheses that include interaction effects should be of more interest to educational researchers, especially since issues related to centering and interpretation of the variance inflation factor have been
introduced. The purpose of this paper was to examine interaction effects in the context of centered versus uncentered variables and the variance inflation factor, especially upon the interpretation of interaction effects. Results indicated that centering of variables was required when examining interaction effects, uncentered variables impacted the variance inflation factor values, and separate regression equations have important interpretation outcomes in the presence of non-significant interaction effects.