Reinforced Informativeness Optimization for Long-Form Retrieval-Augmented Generation

Fuente: arXiv
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Main Authors: Wang, Yuhao, Ren, Ruiyang, Wang, Yucheng, Zhao, Wayne Xin, Liu, Jing, Wu, Hua, Wang, Haifeng
Format: Preprint
Published: 2025
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author Wang, Yuhao
Ren, Ruiyang
Wang, Yucheng
Zhao, Wayne Xin
Liu, Jing
Wu, Hua
Wang, Haifeng
author_facet Wang, Yuhao
Ren, Ruiyang
Wang, Yucheng
Zhao, Wayne Xin
Liu, Jing
Wu, Hua
Wang, Haifeng
contents Long-form question answering (LFQA) requires open-ended long-form responses that synthesize coherent, factually grounded content from multi-source evidence. This makes reinforcement learning (RL) reward design critical. The reward must be verifiable for faithful grounding and stable optimization. However, many standard rewards assume a unique target with an exact-match notion of correctness, which fits short-form QA and math but breaks in LFQA. As a result, current RAG systems still lack verifiable reward mechanisms, yielding unstable feedback signals and suboptimal optimization outcomes. We propose RioRAG, a framework for reinforced verifiable informativeness optimization. First, it defines informativeness as a measurable and externally verifiable objective for RL. Second, RioRAG uses nugget-centric verification with cross-source checks to enable self-evolution of smaller LLMs and to provide denser, action-discriminative rewards that mitigate reward sparsity and stabilize optimization. This formulation avoids handcrafted supervision for the policy model and strong teacher-model distillation, relying instead on externally verifiable feedback. Experiments on LongFact and RAGChecker show that RioRAG achieves higher factual recall and faithfulness, establishing verifiable reward modeling as a foundation for trustworthy long-form RAG. Our codes are available at https://github.com/RUCAIBox/RioRAG.
format Preprint
id arxiv_https___arxiv_org_abs_2505_20825
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reinforced Informativeness Optimization for Long-Form Retrieval-Augmented Generation
Wang, Yuhao
Ren, Ruiyang
Wang, Yucheng
Zhao, Wayne Xin
Liu, Jing
Wu, Hua
Wang, Haifeng
Computation and Language
Long-form question answering (LFQA) requires open-ended long-form responses that synthesize coherent, factually grounded content from multi-source evidence. This makes reinforcement learning (RL) reward design critical. The reward must be verifiable for faithful grounding and stable optimization. However, many standard rewards assume a unique target with an exact-match notion of correctness, which fits short-form QA and math but breaks in LFQA. As a result, current RAG systems still lack verifiable reward mechanisms, yielding unstable feedback signals and suboptimal optimization outcomes. We propose RioRAG, a framework for reinforced verifiable informativeness optimization. First, it defines informativeness as a measurable and externally verifiable objective for RL. Second, RioRAG uses nugget-centric verification with cross-source checks to enable self-evolution of smaller LLMs and to provide denser, action-discriminative rewards that mitigate reward sparsity and stabilize optimization. This formulation avoids handcrafted supervision for the policy model and strong teacher-model distillation, relying instead on externally verifiable feedback. Experiments on LongFact and RAGChecker show that RioRAG achieves higher factual recall and faithfulness, establishing verifiable reward modeling as a foundation for trustworthy long-form RAG. Our codes are available at https://github.com/RUCAIBox/RioRAG.
title Reinforced Informativeness Optimization for Long-Form Retrieval-Augmented Generation
topic Computation and Language
url https://arxiv.org/abs/2505.20825