We compared the MPNN and linear regression models for predicting the solvation energy in water using the training and test data sets described in the previous section. As shown in Figure , our MPNN model has a Mean Absolute Error (MAE) of 0.44 kcal/mol-2.3× better than the 1.0 kcal/mol MAE of the linear regression model. The increased accuracy of the MPNN can be traced to the limited complexity available to the linear regression model.