Thanks :-) The algorithm is unsupervised, so it doesn't take any labels (i.e., party) into account. A senator is considered to be an anomaly when its 172 votes

Thanks :-) The algorithm is unsupervised, so it doesn't take any labels (i.e., party) into account. A senator is considered to be an anomaly when its 172 votes are too dissimilar from those of all the other senators.