To investigate the differences in the electronic state of tungsten during electrochemical reduction, we turned to XPS. The electrochromism occurs due to the injection of electrons into the material, but what electronic states result and how these contribute to the optical response of hexagonal tungsten oxide is debated in the literature. For plasmonic electrochromism, these electrons occupy the conduction band of the material, which increases the electron concentration or volume of LSPR active material, leading to increased LSPR extinction. For polaronic electrochromism, the electrons are localized on WO6 octahedra by distorting the surrounding crystal lattice. The optical response is the result of the hopping of these electrons to nearby octahedra of differing valence state through the absorption of a photon. The electrochromic mechanism is thus correlated with the degree of charge localization, which was probed using XPS to determine if the electronic states depend on the intercalation sites occupied by the cation during reduction.