Web-scale Surface and Syntactic n-gram Features for Dependency Parsing
Table 4: Surface n-gram queries from the wsj and English Web Treebank that do not receive features from Web1T and Google Books.
['Corpus', 'Not Present', '%']
Web1T contains approximately double the total number of n-grams as Google Books. The intersection of these queries is 24.7% of the total, showing that the two corpora have small but substantive differences in word distributions; this may partially explain why our combined feature experiments work so well. However, the similar performance of surface n-gram features extracted from these sources suggests Web1T contains substantial noise.