Table 3. Statistical Metrics Used to Evaluate the Accuracy of Binding Free Energies Calculated for the CHK1 Data Setsa.
| simulation | MUE [kJ mol–1] | RMSE [kJ mol–1] | Kendall τ | Spearman ρ |
|---|---|---|---|---|
| GAFF (subset 1) | 1.7 [1.61–1.78] | 3.1 [2.93–3.27] | 0.3 [0.27–0.38] | 0.5 [0.36–0.55] |
| OpenFF (subset 1) | 1.5 [1.39–1.67] | 2.7 [2.44–2.90] | 0.5 [0.39–0.52] | 0.7 [0.60–0.71] |
| GROMOS FF (subset 1) | 2.2 [2.16–2.30] | 4.1 [4.03–4.23] | 0.3 [0.20–0.39] | 0.4 [0.30–0.49] |
| null model (subset 1) | 1.5 | 2.8 | 0 | 0 |
| GAFF (subset 2) | 4.2 [4.16–4.24] | 7.4 [7.29–7.45] | 0.3 [0.31–0.34] | 0.5 [0.47–0.51] |
| OpenFF (subset 2) | 3.7 [3.69–3.78] | 6.8 [6.69–6.88] | 0.5 [0.52–0.56] | 0.7 [0.67–0.71] |
| null model (subset 2) | 4.8 | 8.6 | 0 | 0 |
a
MUE and correlation metrics (τ and ρ) relate to absolute binding free energies, whereas RMSE corresponds to all pairwise relative binding free energies. Numbers reported correspond to the mean, with upper and lower bounds of the 95% confidence interval in square brackets. Errors used to perform the bootstrapping analysis correspond to standard deviations over the five random seeds, with the exception of simulations with the GROMOS force field where they had been estimated using Gaussian error approximation.54 The MUE and RMSE values presented here do not match exactly those reported in ref (54) due to the different re-centering procedures to obtain MUE values and different error propagation.