Learn to Resolve Conversational Dependency: A Consistency Training Framework for Conversational Question Answering

One of the main challenges in conversational question answering (CQA) is to resolve the conversational dependency, such as anaphora and ellipsis. However, existing approaches do not explicitly train QA models on how to resolve the dependency, and thus these models are limited in understanding human dialogues. In this paper, we propose a novel framework, EXCORD (Explicit guidance on how to resolve Conversational Dependency) to enhance the abilities of QA models in comprehending conversational context. EXCORD first generates self-contained questions that can be understood without the conversation history, then trains a QA model with the pairs of original and self-contained questions using a consistency-based regularizer. In our experiments, we demonstrate that EXCORD significantly improves the QA models' performance by up to 1.2 F1 on QuAC (Choi et al., 2018), and 5.2 F1 on CANARD (Elgohary et al., 2019), while addressing the limitations of the existing approaches. 1 † Corresponding author 1 Our models and code are available at: https://github.com/dmis-lab/excord 2 While the term "context" usually refers to the evidence document from which the answer is extracted, in CQA, it refers to conversational context.