Towards Transparent RAG: Fostering Evidence Traceability in LLM Generation via Reinforcement Learning

Fuente: arXiv
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Main Authors: Ren, Jingyi, Xu, Yekun, Wang, Xiaolong, Li, Weitao, Wang, Ante, Ma, Weizhi, Liu, Yang
Format: Preprint
Published: 2025
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author Ren, Jingyi
Xu, Yekun
Wang, Xiaolong
Li, Weitao
Wang, Ante
Ma, Weizhi
Liu, Yang
author_facet Ren, Jingyi
Xu, Yekun
Wang, Xiaolong
Li, Weitao
Wang, Ante
Ma, Weizhi
Liu, Yang
contents Retrieval-Augmented Generation (RAG) delivers substantial value in knowledge-intensive applications. However, its generated responses often lack transparent reasoning paths that trace back to source evidence from retrieved documents. This opacity not only compromises the interpretability of the output but also limits the model's ability to fully exploit the provided context. To address this, we propose TRACE (Transparent RAG with evidenCE tracing), a framework designed to enhance evidence traceability in Large Language Models (LLMs) through reinforcement learning (RL). TRACE guides LLMs to produce structured outputs with explicit evidence citations by prompting and rewarding evidence relevance and proper formatting, alongside accuracy, to optimize structured traceability. To ensure training stability with multiple reward signals, we further introduce an adaptive strategy for merging rewards and adopt a stabilized KL-divergence estimator. Experiments on three multi-hop QA datasets using Qwen2.5-7B-Instruct and Llama-3.1-8B-Instruct show that TRACE achieves both transparent, evidence-attributed outputs and accuracy improvements of 10-30%. The resulting performance is comparable to advanced commercial LLMs (e.g., OpenAI o1, DeepSeek-R1). Further analyses demonstrate strong generalization capabilities to unseen tasks. Our code is publicly available now.
format Preprint
id arxiv_https___arxiv_org_abs_2505_13258
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Towards Transparent RAG: Fostering Evidence Traceability in LLM Generation via Reinforcement Learning
Ren, Jingyi
Xu, Yekun
Wang, Xiaolong
Li, Weitao
Wang, Ante
Ma, Weizhi
Liu, Yang
Computation and Language
Retrieval-Augmented Generation (RAG) delivers substantial value in knowledge-intensive applications. However, its generated responses often lack transparent reasoning paths that trace back to source evidence from retrieved documents. This opacity not only compromises the interpretability of the output but also limits the model's ability to fully exploit the provided context. To address this, we propose TRACE (Transparent RAG with evidenCE tracing), a framework designed to enhance evidence traceability in Large Language Models (LLMs) through reinforcement learning (RL). TRACE guides LLMs to produce structured outputs with explicit evidence citations by prompting and rewarding evidence relevance and proper formatting, alongside accuracy, to optimize structured traceability. To ensure training stability with multiple reward signals, we further introduce an adaptive strategy for merging rewards and adopt a stabilized KL-divergence estimator. Experiments on three multi-hop QA datasets using Qwen2.5-7B-Instruct and Llama-3.1-8B-Instruct show that TRACE achieves both transparent, evidence-attributed outputs and accuracy improvements of 10-30%. The resulting performance is comparable to advanced commercial LLMs (e.g., OpenAI o1, DeepSeek-R1). Further analyses demonstrate strong generalization capabilities to unseen tasks. Our code is publicly available now.
title Towards Transparent RAG: Fostering Evidence Traceability in LLM Generation via Reinforcement Learning
topic Computation and Language
url https://arxiv.org/abs/2505.13258