Figure plots the error in each energy component, for each S22 dimer, in several basis sets. We restrict out attention to the best-performing Pople and Karlsruhe basis sets that were identified in Section 4 .2, omitting the Dunning basis sets since the S66 results suggest that comparable, high-quality XSAPT + MBD energetics can be obtained more efficiently using def2-TZVPD and def2-QZVPD. Examining the electrostatic energies in Fig. , we notice that 6-311++G(d,p) exhibits errors 1.0 kcal/mol for several of the electrostaticallydominated systems (dimers 1-7 in Fig. ), with the largest errors for (H 2 O) 2 and (HCO 2 H) 2 (dimers 2 and 3, respectively). With additional polarization functions, to obtain 6-311++G(3df,2pd), the electrostatic errors for these same complexes are comparable to those obtained using def2-TZVPD or def2-QZVPD. More surprising is that 6-311++G(3df,2pd) outperforms both Karlsruhe basis sets for the induction energies (Fig. ). That said, errors in the exchange energies (Fig. ) are significantly larger for both Pople basis sets than they are for either Karlsruhe basis set. This is especially true for the formic acid dimer (system #3) and for the four π-stacked dimers, systems 11-15, representing (respectively) the dimers of benzene, pyrazine, Fig. : MAEs in energy components for the S22 dimers, computed at the XSAPT + MBD level in the basis sets that are shown and compared to benchmark energy components computed at the SAPT2+(3)/aug-cc-pVTZ level. Shaded regions delineate the electrostatics-dominated dimers (1-7), the dispersion-dominated dimers (8-15), and the dimers with mixedinfluence interactions (16-22). Note that the energy scale is different in each panel.