Building Open-Retrieval Conversational Question Answering Systems by Generating Synthetic Data and Decontextualizing User Questions

Christos Vlachos, Nikolaos Stylianou, Alexandra Fiotaki, Spiros Methenitis, Elisavet Palogiannidi, Themos Stafylakis, Ion Androutsopoulos


Abstract
We consider open-retrieval conversational question answering (OR-CONVQA), an extension of question answering where system responses need to be (i) aware of dialog history and (ii) grounded in documents (or document fragments) retrieved per question. Domain-specific OR-CONVQA training datasets are crucial for real-world applications, but hard to obtain. We propose a pipeline that capitalizes on the abundance of plain text documents in organizations (e.g., product documentation) to automatically produce realistic OR-CONVQA dialogs with annotations. Similarly to real-world humanannotated OR-CONVQA datasets, we generate in-dialog question-answer pairs, self-contained (decontextualized, e.g., no referring expressions) versions of user questions, and propositions (sentences expressing prominent information from the documents) the system responses are grounded in. We show how the synthetic dialogs can be used to train efficient question rewriters that decontextualize user questions, allowing existing dialog-unaware retrievers to be utilized. The retrieved information and the decontextualized question are then passed on to an LLM that generates the system’s response.
Anthology ID:
2025.sigdial-1.52
Volume:
Proceedings of the 26th Annual Meeting of the Special Interest Group on Discourse and Dialogue
Month:
August
Year:
2025
Address:
Avignon, France
Editors:
Frédéric Béchet, Fabrice Lefèvre, Nicholas Asher, Seokhwan Kim, Teva Merlin
Venue:
SIGDIAL
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Publisher:
Association for Computational Linguistics
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Pages:
641–657
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URL:
https://aclanthology.org/2025.sigdial-1.52/
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Cite (ACL):
Christos Vlachos, Nikolaos Stylianou, Alexandra Fiotaki, Spiros Methenitis, Elisavet Palogiannidi, Themos Stafylakis, and Ion Androutsopoulos. 2025. Building Open-Retrieval Conversational Question Answering Systems by Generating Synthetic Data and Decontextualizing User Questions. In Proceedings of the 26th Annual Meeting of the Special Interest Group on Discourse and Dialogue, pages 641–657, Avignon, France. Association for Computational Linguistics.
Cite (Informal):
Building Open-Retrieval Conversational Question Answering Systems by Generating Synthetic Data and Decontextualizing User Questions (Vlachos et al., SIGDIAL 2025)
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PDF:
https://aclanthology.org/2025.sigdial-1.52.pdf