Lubinski and Humphreys (1990) illustrated how moderator effects uncovered using hierarchical multiple regression procedures may be spurious and that the predictor-criterion functional relationship may be better characterized by a nonlinear function. They recommended concurrently inspecting nonlinear functions when examining moderator effects. This article reviews the evidence presented by Lubinski and Humphreys to substantiate their argument and the generality of their findings beyond their data. Although an examination of nonlinear functions may be justified in their specific illustration, the blanket recommendation of inspecting polynomial terms when examining moderator effects is troublesome and may itself lead to spurious conclusions.
