Higher-Twist Ambiguities in the Determination ofsin2θW

It is shown how present measurements of ${{sin}^2\theta }_{\mathrm{W}}$ are hampered by contributions of higher-twist operators, which are even more important than recently calculated electro-weak radiative corrections. The resulting limit of accuracy for measurements of ${{sin}^2\theta }_{\mathrm{W}}$ is estimated to be of the order of 5% at presently available energies.