Fig. 5.

Signed error Δ_id of individual predictions. The calculated pK_a was matched to the experimental pK_a for each compound (indicated by the SAMPL6 pKa ID) and the deviation from the experimental value represented as a bar. Observations for the same compound have the same color. a: pK_a were directly estimated from the quantum mechanical free energy differences. b: The quantum mechanical pK_a were corrected with the global linear model. c: compounds were corrected depending on their membership in subsets 1 or 2 with the piecewise linear model.