1. A method comprising: receiving text data items; receiving a set of classes into which the text data items are to be classified; selecting a phrase-based classifier to classify the text data items into the set of classes; applying the phrase-based classifier to classify the text data items into the classes, the applying including: creating a controlled vocabulary pertaining to classifying the text data items into the set of classes; building phrases based on the text data items and the controlled vocabulary; and classifying, using at least one processor, the text data items into the set of classes based on the phrases.