A Unified Understanding of Deep NLP Models for Text Classification

TL;DR

This paper introduces DeepNLPVis, a visual analysis tool that uses mutual information to provide a unified, multi-level understanding of deep NLP models for text classification, covering both low-level and high-level features.

Contribution

It presents a novel mutual information-based measure and a comprehensive visualization framework for analyzing various NLP models within a single, unified approach.

Findings

Effective identification of model and sample issues

Enhanced understanding of word and phrase importance

Facilitated model comparison and improvement

Abstract

The rapid development of deep natural language processing (NLP) models for text classification has led to an urgent need for a unified understanding of these models proposed individually. Existing methods cannot meet the need for understanding different models in one framework due to the lack of a unified measure for explaining both low-level (e.g., words) and high-level (e.g., phrases) features. We have developed a visual analysis tool, DeepNLPVis, to enable a unified understanding of NLP models for text classification. The key idea is a mutual information-based measure, which provides quantitative explanations on how each layer of a model maintains the information of input words in a sample. We model the intra- and inter-word information at each layer measuring the importance of a word to the final prediction as well as the relationships between words, such as the formation of phrases. A multi-level visualization, which consists of a corpus-level, a sample-level, and a word-level visualization, supports the analysis from the overall training set to individual samples. Two case studies on classification tasks and comparison between models demonstrate that DeepNLPVis can help users effectively identify potential problems caused by samples and model architectures and then make informed improvements.