  Kohn-Sham inversion, that is, the finding of the exact Kohn-Sham potential
for a given density, is difficult in localized basis sets. We study the
precision and reliability of several inversion schemes, finding estimates of
density-driven errors at a useful level of accuracy. In typical cases of
substantial density-driven errors, HF-DFT is almost as accurate as DFT
evaluated on CCSD(T) densities. A simple approximation in practical HF-DFT also
makes errors much smaller than the density-driven errors being calculated. Two
paradigm examples, stretched NaCl and the HO$\cdot$Cl$^-$ radical, illustrate
just how accurate HF-DFT is.
