Multimetallic catalysts and qubit candidate molecules frequently exhibit strong or static electron correlation, in which a qualitatively correct depiction of the wave function requires the consideration of multiple electronic configurations on equal footing. However, for such systems, the standard complete active space self-consistent field (CASSCF) method with realistic active spaces is far more costly than necessary. This is necessarily true even when using density matrix renormalization group (DMRG) techniques, which extend the applicability of CASSCF to active spaces with many dozens of orbitals, since it is the complete active space itself which is larger than necessary: CASSCF includes a huge number of completely unrealistic electronic configurations, such as highly charge-separated states in which active electrons all gather in one region of the molecule. This observation motivates the development and deployment of methods such as generalized active space SCF (GASSCF) in which electronic configurations are restricted to only those in which the electron occupancies of specified subspaces lie within specified ranges. However, even GASSCF, which includes all possible product states of the subspace wave functions, may be over-complete: it has been shown that multimetallic molecules with complicated magnetic interactions among their metal ions can be modeled with highly compact wave functions, involving only a tiny fraction of all possible product states, when localized-orbital frameworks are used. That is to say, electron correlation between open-shell metal ions is much "less strong" than electron correlation within such open shells: strong electron correlation is sometimes a short-range phenomenon.