Accurate Unlexicalized Parsing

Klein & Manning, 2003, Accurate Unlexicalized Parsing (Proceedings of the 41st Annual Meeting of ACL)

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9 Final Results

What did Klein and Manning’s final unlexicalized parser achieve, and how did it compare?

On section 23 (sentences ≤ 40 words): LP 86.9, LR 85.7, F1 86.3, better than Magerman (1995) and Collins (1996) but below Charniak (1997) and Collins (1999, 88.7/88.6). Development F1 climbed from 77.77 (markovized baseline) to 87.04 through the annotations.

step	dev F1
raw treebank grammar	72.62
markovized, \(v \le 2\), \(h \le 2\)	77.77
+ unary marks, TAG-PA, SPLIT-IN	81.19
+ lexeme splits, TMP-NP, GAPPED-S, POSS-NP, SPLIT-VP	85.72
+ BASE-NP, DOMINATES-V, RIGHT-REC-NP	87.04

Klein & Manning, 2003, Accurate Unlexicalized Parsing (Proceedings of the 41st Annual Meeting of ACL), §9, p. 430

Source

Dan Klein and Christopher D. Manning. 2003. Accurate Unlexicalized Parsing. In Proceedings of the 41st Annual Meeting of the Association for Computational Linguistics, pp. 423–430. https://aclanthology.org/P03-1054/