Substitute Based SCODE Word Embeddings in Supervised NLP Tasks
Table 3: Word token coverage for word embeddings.
['Word Embeddings', 'Chunking Training', 'Chunking Development', 'Chunking Test', 'NER Training & Development', 'NER Test', 'NER OOD', 'Dependency Parsing Training', 'Dependency Parsing Test']
For each task, an unknown word in the training or test phase is replaced with the word embedding of unknown tag. Thus, the word embedding method with high coverage suffers less from unknown words, which in turn effects its success. GCA NLM has the lowest coverage in all tasks, which may explain its level of performance.