Comparison of performance at class level. For each class, sensitivity and F-score values resulting from phylogenetic learning based on a 16S rRNA gene NJ or UPGMA tree are compared to those obtained by flat multi-class classification. Four plots are given. The X-axis corresponds to thresholds set on the corresponding metric values. Threshold steps of 0.01 are chosen. For each threshold, flat multi-class classification is evaluated at class level and those classes with metric values smaller than or equal to the threshold are selected. Classification performance by phylogenetic learning is analyzed at class level for each set of classes. The Y-axis on the left projects the number of phylogenetic learning classes that have a higher metric value than those obtained by flat multi-class classification. The red line expresses this number, relative to the size of the corresponding set (Y-axis on the right).