RAGferee: Building Contextual Reward Models for Retrieval-Augmented Generation

Andrei Catalin Coman, Ionut Teodor Sorodoc, Leonardo F. R. Ribeiro, Bill Byrne, James Henderson, Adrià de Gispert


Abstract
Existing Reward Models (RMs), typically trained on general preference data, struggle in Retrieval Augmented Generation (RAG) settings, which require judging responses for faithfulness to retrieved context, relevance to the user query, appropriate refusals when context is insufficient, completeness and conciseness of information. To address the lack of publicly available RAG-centric preference datasets and specialised RMs, we introduce RAGferee, a methodology that repurposes question-answering (QA) datasets into preference pairs that prioritise groundedness over stylistic features, enabling the training of contextual RMs better suited to judging RAG responses. Using RAGferee, we curate a small preference dataset of 4K samples and fine-tune RMs ranging from 7B to 24B parameters. Our RAG-centric RMs achieve state-of-the-art performance on ContextualJudgeBench, surpassing existing 70B+ RMs trained on much larger (up to 2.4M samples) general corpora, with an absolute improvement of +15.5%.
Anthology ID:
2025.emnlp-main.414
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
EMNLP
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Publisher:
Association for Computational Linguistics
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Pages:
8175–8222
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URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.414/
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Cite (ACL):
Andrei Catalin Coman, Ionut Teodor Sorodoc, Leonardo F. R. Ribeiro, Bill Byrne, James Henderson, and Adrià de Gispert. 2025. RAGferee: Building Contextual Reward Models for Retrieval-Augmented Generation. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 8175–8222, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
RAGferee: Building Contextual Reward Models for Retrieval-Augmented Generation (Coman et al., EMNLP 2025)
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