Disregarding these worsens correlation with experiment, yielding a Pearson r of 0.72 ± 0.16, Kendall 𝜏 of 0.43 ± 0.19, and a RMSE of 2.50 ± 0.24 kcal/mol. This rather poor correlation by comparison to the other datasets may in part be explained by the narrower activity range covered by the ligands in this series (Fig. ). Except from two (ligands 60 and 65), the ligands cover an approximately 2 kcal/mol activity range. This is possibly too narrow a range to distinguish between binding, especially given the size of the uncertainties in our calculated estimates.