188 additional features were later removed for having zero values for all molecules, leaving 871 features. Finally, we removed highly correlated features to improve model stability. We first calculated each feature's accuracy when used individually to train a logistic regression classifier for predicting synthesizability. We then computed Pearson correlation coefficients for all unique feature pairs, identified pairs with coefficients greater than 0.90 ("highly correlated pairs"), and removed the feature from each highly correlated pair that had the lower logistic regression classifier accuracy when fitted individually to synthesizability labels. This procedure removed 556 features, leaving 315 Mordred features.