The parity plot in Fig. shows the joint distribution of predicted and actual values of the (standardized and, in the case of Henry coefficients, log 10 -transformed) adsorption properties in the test data set-the simulated unobserved entries of A (0.4) . The density is greatest along the diagonal line of equality, indicating that the recommendation system is providing predictive value. The RMSE and Spearman's rank correlation coefficient on the test data is 0.6 and 0.77, respectively.