How should we interpret all of the architectures approaching a MAE of ∼4 kcal/mol on the RGD1 testing split? To answer this the reader should consider that there are several known sources of irreducible error in RGD1-indeed to some extent all available computational TS datasets suffer from these issues. These sources include the inaccuracy of the underlying DFT method (B3LYP-D3/TZVP), incomplete conformational sampling of TSs and reactants, and the potential inclusion of TSs that correspond to unintended reactions (i.e., they connect a reactant and product that are different than the label). Because we are testing on DFT-level E a values and not experimental values, the absolute DFT errors should not contribute to the irreducible error for this particular learning task; but incomplete conformational sampling and mislabeled TSs still represent sources of irreducible error. Below we will provide some lower bound estimates of the latter errors, but cumulatively they are expected to easily amount to an uncertainty of 4 kcal/mol across the entire dataset. As such, we interpret the prediction errors of all the models as effectively approaching the irreducible error of this prediction task.