Graph Convolutional Networks for Text Classification
Liang YaoChengsheng MaoYuan Luo
Introduces Text GCN, a framework that models an entire text corpus as a graph of word co-occurrences and document-word relations to classify documents without external embeddings, outperforming existing methods especially when labeled training data is scarce.
Text classification is a critical capability across many automated operations, including spam detection, document routing, opinion mining, and clinical record analysis. Standard deep learning models such as convolutional and recurrent neural networks primarily capture local, sequential word order but often fail to model broader, corpus-wide word co-occurrence relationships. This article evaluates whether framing an entire text collection as a single, heterogeneous graph network can outperform conventional deep learning techniques and reduce reliance on pre-trained external word representations.
The article introduces and evaluates Text Graph Convolutional Networks (Text GCN), a method that converts document classification into a node classification task. The approach builds a single unified graph where words and documents serve as interconnected nodes. Document-to-word relationships are weighted by standard statistical term importance, while word-to-word relationships are established via global co-occurrence across text windows. A two-layer graph convolutional network then jointly learns embeddings for both words and documents using only the training labels. The researchers tested this framework across five standard benchmark datasets spanning news articles, medical literature, and short movie reviews, comparing it against multiple established baselines.
The findings show that Text GCN outperforms competing baseline models on four out of five datasets, demonstrating particular strength on longer documents. For example, on the Ohsumed medical dataset, Text GCN achieved 68.36% accuracy, exceeding all baselines including convolutional and recurrent networks. Second, the method demonstrates high resilience when labeled data is scarce: on the R8 dataset, Text GCN achieved 88.30% accuracy using only 1% of the labeled training data, surpassing several baselines trained on the entire dataset. Third, Text GCN successfully generates highly interpretable and discriminative representations for words and documents without requiring pre-trained embeddings or external knowledge bases. Finally, the model proved less effective on single-sentence sentiment data (76.74% on the movie review dataset), where local word order and syntax dominate and sparse text structures limit graph edge formation.
These results demonstrate that organizations can achieve state-of-the-art text categorization performance while substantially reducing the cost and effort of manual data labeling. Because the model operates effectively in low-data regimes without requiring external linguistic datasets, it minimizes deployment friction for specialized, proprietary, or domain-specific vocabularies. However, practitioners should be aware of a fundamental technical trade-off: the model is inherently transductive, meaning the entire dataset graph (including unlabeled test documents) is required during training, making immediate real-time classification of new, unseen documents impractical without retraining or architectural extensions.
Organizations handling large document collections or domain-specific classification tasks should consider piloting graph-based classification, particularly where labeled training data is limited. Before deploying in real-time operational workflows, future development must focus on extending the architecture to inductive settings, incorporating graph attention mechanisms, or evaluating fast sampling frameworks to support on-demand inference on new documents.
- Paper: Semi-Supervised Classification with Graph Convolutional Networks, Thomas N. Kipf et al. (2017). Introduces the foundational semi-supervised Graph Convolutional Network (GCN) architecture and layer-wise propagation rule directly adapted by Text GCN.
- Paper: Revisiting Semi-Supervised Learning with Graph Embeddings, Zhilin Yang et al. (2016). Presents Planetoid for graph-based semi-supervised learning and text classification, which serves as a core baseline and conceptual precursor to Text GCN.
- Paper: Convolutional Neural Networks on Graphs with Fast Localized Spectral Filtering, Michaël Defferrard et al. (2016). Establishes spectral graph convolutions with fast localized filtering on irregular structures, laying the mathematical groundwork for modern GCN formulations.
- Paper: Inductive Representation Learning on Large Graphs, William L. Hamilton et al. (2017). Develops inductive representation learning and neighborhood aggregation over graphs, providing vital context on neural message passing.
- Paper: Convolutional Neural Networks for Sentence Classification, Yoon Kim (2014). Provides the foundational baseline architecture for applying standard convolutional networks to word sequences for sentence and text classification.
- Paper: Bag of Tricks for Efficient Text Classification, Armand Joulin et al. (2017). Introduces fastText, establishing a standard competitive baseline for efficient text and document categorization.
- Paper: The Graph Neural Network Model, Franco Scarselli et al. (2009). Pioneers the original Graph Neural Network framework for processing relational structures and node-level supervised tasks.
- Paper: Simplifying Graph Convolutional Networks, Felix Wu et al. (2019). Simplifies graph convolutional architectures by removing non-linearities and demonstrates competitive performance on downstream text classification tasks.
- Paper: A Comprehensive Survey on Graph Neural Networks, Zonghan Wu et al. (2019). Provides a comprehensive taxonomy and survey of graph neural network paradigms, contextualizing corpus-level graph convolution models.
- Paper: Cluster-GCN: An Efficient Algorithm for Training Deep and Large Graph Convolutional Networks, Wei-Lin Chiang et al. (2019). Addresses the scalability and memory bottlenecks of training GCNs on large graphs, such as whole-corpus text graphs, via clustering-based mini-batching.
- Paper: Predict then Propagate: Graph Neural Networks meet Personalized PageRank, Johannes Gasteiger et al. (2019). Decouples neural prediction from graph propagation via personalized PageRank to overcome the over-smoothing limitations inherent in multi-layer GCNs.
- Paper: Simple and Deep Graph Convolutional Networks, Ming Chen et al. (2020). Proposes techniques to enable deeper graph convolutional networks without suffering from severe over-smoothing.
- Paper: How Powerful are Graph Neural Networks?, Keyulu Xu et al. (2019). Theoretically characterizes the expressive power and representational limits of neighborhood aggregation schemes in GCNs.
