In particular, we analyzed the parsers' behavior on 5,039 sentences in sections 1, 22 and 24 of the Penn treebank.
we classified each sentence into one of three classes: those where the self-trained parser's f -score increased relative to the baseline parser's f -score, those where the f -score remained the same, and those where the self-trained parser's f -score decreased relative to the baseline parser's f -score.