In the present work, we apply DC-DFT to an electronpolaron in TiO 2 and a hole-polaron in doped SiO 2 . Functional-versus density-driven errors have not previously been considered in this context, but the open-shell nature of polaron defects suggests that the procedure may be advantageous in these cases. (This supposition is supported by results from a density-sensitivity metric, as discussed below.) Within the materials science community there is enormous interest in polaron transport and trapping in transition metal oxides, yet delocalization error in DFT presents a significant conundrum for computational modeling of these species. To introduce the DC-DFT formalism, let us express the energy functional in the form