Different methods of finding the Rouse relaxation times tau(e), demarcating the onset of entanglement effects, were evaluated for entangled solutions of high molecular weight polystyrene in diethyl phthalate. Five expressions were utilized, involving variously the zero shear viscosity, the storage modulus at frequencies just beyond the rubbery plateau, the terminal Andrade creep region in the retardation spectrum, and the recoverable creep compliance. Values Of tau(e) determined by a procedure which assumes that the deformation modes are additive in the strain were substantially larger than the Rouse times extracted from the storage modulus by assuming stress additivity. (C) 2004 The Society of Rheology.