with two key differences: (i) the exchange-correlation functional is replaced with an "ontop" functional E ot which is a functional of both the density ρ and on-top density Π, and (ii) the density arguments D pq , ρ, and Π come from a multiconfigurational (generally CASSCF) wave function. In practice, the on-top functional is a "translated" functional (most often translated PBE, 28 tPBE) in which the density and on-top density are used to manufacture effective spin densities for use in the KS-DFT energy expression (eq. 3). Thus, as MC-PDFT more-or-less shares eq. 3 with KS-DFT, MC-PDFT appears promising for attenuating part of the active space inconsistency error, especially when paired with automated methods for choosing the active space in a reliable and consistent fashion. While MC-PDFT has been tested on a wide variety of systems and excitations, it has yet to be tested in a high-throughput fashion for reactivity.