Fig 3. Variable importance from random forest models.

Importance of each variable in predicting virulence in random forest models applied to all known human RNA viruses and zoonotic viruses only, calculated as the average decrease in Gini impurity following a tree split based on that predictor and scaled against the most informative predictor within each random forest to give a relative measure. Points denote mean values across 200 random forest models with alternative training/test partitions. Error bars denote ± 1 standard deviation. Colour key denotes type of predictor variable. Supporting data are available via figshare: 10.6084/m9.figshare.7406441.v3 (https://figshare.com/articles/Data_and_supporting_R_script_for_Tissue_Tropism_and_Transmission_Ecology_Predict_Virulence_of_Human_RNA_Viruses/7406441/3). nh, nonhuman; tr, transmissibility.