Relative accuracy can be quantified as formula_14, so that the mean squared error of a candidate formula_11 is made relative to that of a user-specified formula_10. The relative simplicity term measures the amount that formula_11 deviates from formula_10 relative to the maximum amount of deviation from formula_10. Accordingly, relative simplicity can be specified as formula_20, where formula_21 corresponds to the formula_8 value with the highest permissible deviation from formula_10. With formula_24, the user determines how high the influence of the reference parameter is relative to cross-validation.