Upon closer inspection, a high dependence upon substrate identity was observed, implying that for this subreactome, the most important factor is the reacting halide-nucleophile pair. Overall, the best / worst-in-class catalysts fall neatly into chemical intuition for the reasons highlighted above (Fig. ), and gratifyingly also cluster neatly in the ligand PCA visualization (Fig. ). A sharp divide between best-in-class and worst-in-class ligand clustering is clear and Xantphos, the single ligand that could be either depending upon the precatalyst employed, resides away from the other ligands. Many of the subreactomes also agree with the literature's reactome, but several areas of interest stick out. First, the ArCl + 1˚ amines reactome differs from the literature's. While ArCl + 1˚ amine yield are somewhat dependent upon their reactants' structures, the lack of any significant ligand importance and the dominance of reactant identity suggests to us that this dataset may have some substrate selection bias. A clearer picture of ArCl + 1˚ amines' reactome could be achieved with expansion of the diversity in nucleophiles screened. The second is the little importance placed upon t-BuBrettPhos in ArBr + 1˚ amine's reactome. This may be due to the infrequent usage of t-BuBrettPhos when compared to the other catalysts in the subdataset. In the instances that t-BuBrettPhos was utilized, it was with challenging substrates (hence why it was noted as a best-in-class ligand with z-score-ANOVA-Tukey). In future screens, it could be advantageous to use t-BuBrettPhos more frequently to investigate this further.