Unsupervised Grammar Induction with Depth-bounded PCFG
Table 3: PARSEVAL scores on Eve dataset for all competing systems. These are unlabeled precision, recall and F1 scores on constituent trees without punctuation. Both the right-branching baseline and the best performing system are in bold. (**: p < 0.0001, permutation test)
['System', 'Precision', 'Recall', 'F1']
The right-branching baseline is still the most accurate in terms of PARSEVAL scores, presumably because of the highly right-branching structure of child-directed speech in English. The DB-PCFG system with only one memory depth and 15 non-terminal categories achieves the best performance in terms of F1 score and recall among all the competing systems, significantly outperforming other systems (p < 0.0001, permutation test).