The mixed and gazetteer systems, having a variety of noisy data in their training set, perform much better on the noisy conditions, particularly on Latin-alphabet-non-English data because that is one of the conditions included in its training, while Transactions remains a condition not covered in the training set and so shows less improvement.
because the mixed classifier, and moreso the gazetteer classifier, are oriented to noisy data, on clean data they suffer in performance by 2.5 and 5 F -measure points, respectively.