Due to suggestions that Self Interaction Corrections (SIC), gradient corrections, and short-range electron–electron interactions in the Local (Spin) Density Approximation (L(S)DA) scheme may significantly influence the computed electronic structure for the Mott-insulating (MI) transition metal oxides (TMOS), a comparative study has been made of Hartree Fock (HF) and L(S)DA computations for NiO. Since HF lacks electronic correlation, it overestimates band width (in conductors) and/or band gaps (in insulators). It gives the band gap for NiO two times larger than that in experiment, while LSDA gives the gap one order of magnitude smaller than the experimental value. We demonstrate that the HF results are consistent with some previously believed to be well-understood experiments, while the L(S)DA results are not. It is suggested that HF may offer a better reference state for the development of a LSDA scheme. © 1993 John Wiley & Sons, Inc.