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Potassium-doped barium bismuth oxide ($Ba_{1-x} K_x Bi O_3$), is a famous high temperature superconductor, discovered in the late 1980s~\cite{Sleight_1975, Cava_1988}. Its parent compound, BaBiO$_3$, has a distorted perovskite structure, with a band gap of $\sim 0.2$~eV~\cite{Sleight_1975}. Doping the material, with K for example, suppresses the structural distortions and makes the material superconducting, reaching a transition temperature of nearly 30~K at optimal doping. DFT does not describe the insulating character of the parent compound. Conventional DFT estimates of the electron phonon coupling $\lambda$ within Migdal-Eliasberg theory give a value of 0.34 in the doped compound, too small to account for its superconductivity~\cite{Meregalli_1998}.  Examining the effect of correlations, we found that $\lambda$ is substantially enhanced relative to its DFT estimate to a value of nearly $1.0$, and that this enhancement is responsible for superconductivity in BaBiO$_3$~\cite{Yin_2013}.%  We argue that correlations similarly enhance the electron phonon coupling in other materials proximate to an insulating state, accounting for superconductivity in systems such as HfNCl, borocarbides and buckminsterfullerenes. For these materials the most important type of correlation that needs to be treated is the static  ( in the solid state physicist convention) correlations. Hence a GW, or a hybrid DFT calcuation is enough