We next consider largemolecule isomerization energies, whereas the isomerization energy data sets considered in Section 3 .2 .1 correspond to smaller molecules. Error statistics for the largemolecule isomerization energies are presented in Fig. . As for the barrier height data in Fig. , the maximum errors presented as gray bars in Fig. are averages of the maximum errors across the separate data sets, except that in the present case we exclude the MB16-43 data set from the average. This data set comes from "mindless benchmarking", 154 meaning 43 reactions created at random and having 16 atoms each. The reference energies for this data set are quite large, with an average of |∆E MB16-43 | = 414.7 kcal/mol, which is an order of magnitude larger than |∆E i | for the other data sets considered in Fig. . Since that differences significantly skews the error statistics, we remove MB16-43 from the averages that are given in Fig. . This is an alternative to using WTMAD2, which allows us to consider actual MAEs, by eliminating the one data set that would otherwise swamp the averages.