The asymptotic expansion of the Newmann-to-Dirichlet map under the perturbation of small inclusions in the context of electric impedance tomography was widely studied in the literature under the condition that the materials inside the inclusions are homogeneous and the convergence of the expansion depends on the materials. In this talk, I will discuss the uniformity of this expansion with respect to the materials inside small inclusions. If times permits, I will mention a more general situation where this uniformity still holds. This is a joint work with M. Vogelius