It is also instructive to consider the accuracy of the reference methods themselves. As mentioned above, Hait and Head-Gordon used the RRMSE to benchmark density functional methods against high-level Coupled Cluster references. According to this metric, the best kQEq model reaches an accuracy of 8.1% on the dipole moments of QM9. This can be compared with the reported errors of popular hybrid functionals like PBE0 (5.2%) and B3LYP (7%). However, it should be noted that the benchmark in ref. [44] focuses on very small molecules and includes spin-polarized systems, so that this comparison should not be overinterpreted. Nonetheless, it indicates that kQEq models approach hybrid DFT accuracy at a much reduced cost.