Effect of label bias on ROC scores. Bars show the prediction error measured using 1 - area under the receiver operating characteristic (ROC) curve (1 - AUC) of GeneMANIA where the label bias of unlabeled genes is set to zero or average label (that is, k = 0 or k = mean label). The experiments were run on 400 Gene Ontology (GO) functional classes using 15 yeast association networks that we created from various genomics and proteomics data sources (see Materials and methods). The functional classes are grouped by specificity (defined by number of annotated genes: 3 to 10, 11 to 30, 31 to 100, 101 to 300). Error bars depict the standard error on 100 different predictions in each evaluation category.