Non‐Newtonian viscosity and the primary normal stress difference in steady simple shear flow and the dynamic viscosity and dynamic storage modulus in oscillatory simple shear flow were measured for three viscoelastic fluids. Most of the data were obtained with a Weissenberg Rheogoniometer. The data were used to evaluate a differential model and two integral models, with all three models predicting the same relations for the material functions. The models satisfactorily describe the non‐Newtonian viscosity, dynamic viscosity, and storage modulus data for each solution, but fail to describe the primary normal stress difference data by predicting incorrect slopes in the “power‐law” regions.