At test time, we predictŷ t to be the label type with maximal marginal probability.
we setŷ t to be where z ranges over the label types (e.g., POS or named entity tags) present in D. As noted in the introduction, predicting labels in this way allows for the prediction of any label type present in the database D used at test time, and so we can easily predict label types unseen at training time without any additional retraining.