110414: Smoothed step (Hinge) and Discrete step (Threshold) cannot both be used as basis expansions.

Description

For the Explanatory Variable Expansions (Basis Functions) parameter, the Smoothed step (Hinge) and Discrete step (Threshold) options cannot both be chosen. Using both a step function and a smoothed step function creates strong dependence between each basis function that results in unstable predictions.

Solution

Remove one of the two basis expansions.