Sample toxic external validation predictions from the cluster models. Predictions are shown for 2,2’,4,4’,5-pentachlorodiphenyl ether (CAS 60123–64-0) based on its biological nearest neighbor within the training set chemicals tested in Cluster 17 bioassays, tributyltetradecylphosphonium chloride (CAS 81741–28-8), and for 2,4-difluoro-1-(4-nitrophenoxy)benzene (CAS 28280–37-7) based on its biological nearest neighbor within the training set chemicals tested in Cluster 41 bioassays, prochloraz (CAS 67747–09-5). A subset of the complete profile is shown in both panels, which includes the most influential bioassays on the resulting toxic prediction (i.e., those containing at least one active response between the validation chemical and its biological nearest neighbor). The columns in each profile represent assay identifiers from PubChem (prefixed with “P”) and ToxCast (prefixed with “T”), as listed in Tables 1 and 2. Active results are shown as red rectangles, inactive results are shown as blue rectangles, and untested chemical-bioassay pairs are shown as gray rectangles. Thick bold boxes surround shared active responses.