For 0 < x < 1 [H/M], we compute formation energies of either 1,000 (for PdH x ) or 10,000 (for Pd 0.91 Rh 0.09 H x and Pd 0.91 Ag 0.09 H x ) random configurations per x. Density plots in Figure show the ML screened energies, E(x), for each system. A linear interpolation of the average energy between E(x = 0) and E(x = 1), denoted Ẽ(x), has been subtracted to better visualize the change in convexity as a function of x. The average energy, ⟨E⟩(x), and minimum energy, E min (x), are also plotted for a "10%" sampling of the training data, "100%" sampling of the training data, and the full "ML" screening. The narrowly distributed E(x) for PdH x makes even the "10%" sampling of the training data sufficient to converge ⟨E⟩(x), and E min (x) within 1 meV per metal of the "ML" screening. However, due to the substantially wider E(x) distribution in the alloyed systems, the "10%" sampling is insufficient to even smoothly converge ⟨E⟩(x), and the "ML" screening systematically converges the sampling of low energy configurations with several meV/atom lower E min (x) than the "100%" sampling of the training data.