Compare this to the experimental data presented in fig. . Here, the lattice oxygen evolution is reported for the rutile Ru is difficult to assess where the exact optimum lies, it would however be expected that it lies close to the 10% mark. This is in general agreement with the theoretical analysis shown above which predicts a presence of a LOER maximum between 12.5% and 20%. Some of this discrepancy between experiments and theory could be explained by nickel enrichment of the surface in the real systems . As such there should be more LOER at low nickel content than modelled due to the few nickel present having a high probability of being near or in the surface. At high nickel content the opposite would be expected due to nickel over-saturation in the surface, reducing the likelihood of the Ru-Ni bridge site. The computational methodology has also been Due to requiring three titanium atoms at the surface, these sites are expected to be very rare at low Ti content. By extension, low to negligible LOER activity would be expected at low titanium content. As the Ti content increases, the probability of these three-titanium clusters being in the top layer also rises. Their contribution to LOER is therefore mostly expected at higher Ti content. This is in somewhat agreement with experiments where LOER is not observed at low titanium content but is observed at higher Ti content (x = 0.20) . However, due to the rarity of the identified surface sites, it would be unexpected that these sites are major contributors to LOER at x = 0.20. This discrepancy could be attributed to defects in the structure as these positively correlate with LOER tendency . Specifically, it has been found that the Ru 1-x Ti x O 2 system has oxygen deficiencies around the titanium in the structure . Structural defects like these present a challenge for this computational method that hinges on knowledge of the structure. The method is therefore not expected to accurately represent LOER tendency in structures with major lattice defects. With basis in the computational analysis, it seems probable that the observed LOER is promoted by the defects in the structure.