3.1.3. Error Distributions. Figure plots how the basis-set convergence errors are distributed with respect to zero, for one particular functional using a variety of basis sets and comparing both CP-corrected and uncorrected results. (For other functionals, including double hybrids, see Figs. S4 and S5.) In larger basis sets, the errors distributions narrow considerably and def2-TZVPD is the smallest basis set for which all of the data points lie within ±0.5 kcal/mol of the CBS limit, which is true in that case even without CP correction. For aug-cc-pVDZ and def2-SVPD, the CP-corrected errors are much more tightly grouped together as compared to the uncorrected results, with a mean signed error that tilts toward underbinding but by a much smaller amount as compared to the overbinding that is observed in the absence of CP correction. In the aug-cc-pVXZ data, one can perhaps find justification for the statement that "CP overcorrects for BSSE", yet it is equally true that the uncorrected results systematically underbind the S66 complexes, and as a result the half-CP average is more reliable than either the CP-corrected or uncorrected values of ∆E int . That said, CP correction reduces the MAE with respect to the CBS limit and also significantly reduces the spread of the convergence errors. Quantitative data for each functional and basis set, as measured by root-mean-square deviations from the DFT/CBS limit, can be found in Tables and. These trends are more muddled in the case of Pople basis sets, where CP-DFT does not consistently underor overbind the complexes, and the distribution of CP-DFT convergence errors is centered close to zero. For example, in the case of the BLYP+D3(BJ) functional the mean signed errors range from -0.07 to +0.10 kcal/mol for the four Pople basis sets shown in Fig. ; see Table for the quantitative data. If CP correction is neglected, the dimers are generally overbound, with a mean signed errors ranging up to -2.3 kcal/mol. Karlsruhe basis sets (Fig. ) represent something of an intermediate case, in that CP-corrected results are not always underbound but convergence to the CBS limit is systematic.