Identification of a non-Newtonian power law was used to prove that the model selection framework favours higher complexity models where required. Eleven experimental data points were collected using 1% w/w aqueous carboxymethyl cellulose at different flow rates. As for the Newton's law identification, an expression three with three layers was used, including the shear rate ( 𝛾ṧ) as the only predictor variable. With the afore-mentioned settings, the portfolio of six models, Table , was obtained within 13 min. The mathematically invariant and similar models were discarded. It is worth mentioning that the same power law was found for 𝐶 = {5,6,7}. The resulting portfolio consists of three different models of different complexity.