Comparing the Use of Edited and Unedited Text in Parser Self-Training

We compare the use of edited text in the form of newswire and unedited text in the form of discussion forum posts as sources for training material in a self-training experiment involving the Brown reranking parser and a test set of sentences from an online sports discussion forum. We find that grammars induced from the two automatically parsed corpora achieve similar Parseval fscores, with the grammars induced from the discussion forum material being slightly superior. An error analysis reveals that the two types of grammars do behave differently.