The principal finding of this paper is that the far-field slope has a first-order effect on model age determinations of scarplike landforms in weakly consolidated terrains. Observationally, this can be demonstrated in two ways using the Lake Bonneville and Lahontan shoreline scarps as separate and combined data sets. When one correctly takes into account the far-field slope, one will basically get the same age determination no matter which of these models one uses; conversely, without accounting properly for the effect of far-field slope, one is virtually guaranteed to get an erroneous age determination, no matter which model is used. -from Authors