Numerical models are used to help constrain empirical parameterizations of soil production and transport mechanisms on soil-mantled hillslopes. The neighbourhood algorithm is used to invert soil thickness versus surface curvature data to provide not only more rigorous estimates of model parameter values but determine which of the model parameters are constrained by cosmogenic exposure ages (Heimsath et al., 2000). We show that linear and depth-dependent creep constants can be constrained by simple geomorphometric measurements, such as the distribution of soil thickness on the landform and its relationship to surface curvature. We also show that this unique data set cannot be used on its own to constrain the parameterization of overland flow, another transport mechanism that is thought to play an important role on soil-mantled hillslopes, or to determine if a soil distribution has reached local steady state. We also demonstrate that, to explain the data, soil production must be a function of soil thickness. These conclusions have important implications for our understanding of landscape evolution on medium to long time scales.