Three data sets are worth examining in detail: W4-11, SIE4X4, and DC13, as each exhibits a broad spectrum of errors (Fig. ). The W4-11 data set consists of 140 atomization energies and exhibits the largest variation in the errors amongst the set of functionals examined. Atomization energies make for a rigorous test of performance because there is no opportunity for error cancellation, and it is clear from the W4-11 data that increasing the fraction of exact exchange has a direct and detrimental impact on the accuracy of B(α)LYP+D3 for this particular property. The B3LYP+D3 functional performs substantively better even than B(20)LYP+D3, whose MAE is 7 kcal/mol, and all functionals with α ≥ 30 perform worse for the W4-11 atomization energies than does BLYP+D3. On the other hand, because atomization energies are rarely an observable of interest, poor performance of B(α)LYP+D3 for this property may not be an obstacle to deploying these functionals in practice.