CONQRR: Conversational Query Rewriting for Retrieval with Reinforcement Learning

Anonymous

Abstract: Compared to standard retrieval tasks, passage retrieval for conversational question answering (CQA) poses new challenges in understanding the current user question, as each question needs to be interpreted within the dialogue context. Moreover, it can be expensive to re-train well-established retrievers such as search engines that are originally developed for non-conversational queries. To facilitate their use, we develop a query rewriting model CONQRR that rewrites a conversational question in the context into a standalone question. It is trained with a novel reward function to directly optimize towards retrieval using reinforcement learning and can be adapted to any fixed retriever. We show that CONQRR achieves state-of-the-art results on a recent open-domain CQA dataset containing conversations from three different sources, and is effective for two different fixed retrievers. Our extensive analysis also shows the robustness of CONQRR to out-of-domain dialogues as well as to limited query rewriting supervision.

Paper Type: long