Learned in Translation: Contextualized Word Vectors

Computer vision has benefited from initializing multiple deep layers with weights pretrained on large supervised training sets like ImageNet. Natural language processing (NLP) typically sees initialization of only the lowest layer of deep models with pretrained word vectors. In this paper, we use a deep LSTM encoder from an attentional sequence-to-sequence model trained for machine translation (MT) to contextualize word vectors. We show that adding these context vectors (CoVe) improves performance over using only unsupervised word and character vectors on a wide variety of common NLP tasks: sentiment analysis (SST, IMDb), question classification (TREC), entailment (SNLI), and question answering (SQuAD). For fine-grained sentiment analysis and entailment, CoVe improves performance of our baseline models to the state of the art.

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Results from the Paper


Task Dataset Model Metric Name Metric Value Global Rank Result Benchmark
Sentiment Analysis IMDb BCN+Char+CoVe Accuracy 91.8 # 31
Natural Language Inference SNLI Biattentive Classification Network + CoVe + Char % Test Accuracy 88.1 # 36
% Train Accuracy 88.5 # 54
Parameters 22m # 4
Question Answering SQuAD1.1 DCN + Char + CoVe EM 71.3 # 152
F1 79.9 # 158
Hardware Burden None # 1
Operations per network pass None # 1
Question Answering SQuAD1.1 dev DCN (Char + CoVe) EM 71.3 # 34
F1 79.9 # 37
Sentiment Analysis SST-2 Binary classification BCN+Char+CoVe Accuracy 90.3 # 61
Sentiment Analysis SST-5 Fine-grained classification BCN+Char+CoVe Accuracy 53.7 # 9
Text Classification TREC-6 CoVe Error 4.2 # 9

Methods