Scoring model performance depends on the taxonomic distance of the input set. AUC performance of five different scoring models that vary in the distance of the taxonomic input set. Area under the ROC curves is measured for the taxonomic sets Metazoa (red), Nematoda (yellow) and H. sapiens (blue) versus 200,000 randomly selected hairpins from the set of 3,526,115 C. elegans hairpins. Scoring models "X – Y" have as taxonomic input set all miRNA hairpins from set X after removal of set Y. From these subsets (and the set Hominidae) 781 miRNA hairpins have been randomly selected. The results presented for the random subsets are averages from 50 independent repeats.