Regression toward the mean effects are presented within the field of quantitative structure-activity relationship modeling and in situations in which multilinear regression techniques are considered for model building. The concept is related to the graphical aspect of some scatter plots (experimental vs fitted and fitted vs experimental values). These graphs demonstrate how the point cloud is not always symmetrically distributed along the so-called "ideal" or "desired" line, that is, the bisector of the first and third quadrants. The deviation from the ideal line is fixed, and it is also related to the coefficient of determination. An extrapolation of these regression effects is also discussed within the context of property predictions obtained via the leave-one-out cross-validation technique.