In recent literature, the ratio of the residual depth of indentation to the total depth, hf/hmax, has been shown to be a useful parameter in predicting constraint factor and pile-up during indentation in bulk materials. In this work, hf/hmax is shown to have a simple one-to-one relationship to Sl/S, or the ratio of the slope of the load vs. displacement curve when loading to the elastic stiffness of the contact. Experimentally, the parameter Sl/S is attractive because unlike hf/hmax, it can be determined continuously during loading, using only data near the depth of interest. The elastic stiffness, S, is measured using a forced-oscillation technique, thus allowing Sl/S to be determined as a function of depth. Previous predictions for constraint factor and pileup are recast in terms of Sl/S.