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Main Authors: Liu, Jiayi, Zhang, Jiaxing, Jin, Bowen, Neville, Jennifer
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.08838
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author Liu, Jiayi
Zhang, Jiaxing
Jin, Bowen
Neville, Jennifer
author_facet Liu, Jiayi
Zhang, Jiaxing
Jin, Bowen
Neville, Jennifer
contents Retrieval-augmented generation (RAG) is widely used to augment large language models (LLMs) with external knowledge. However, many benchmark datasets, designed to test RAG performance, comprise many questions that can already be answered from an LLM's parametric memory. This leads to unreliable evaluation. We refer to this phenomenon as knowledge leakage: cases where RAG tasks are solvable without retrieval. This issue worsens over time due to benchmark aging. As benchmarks are reused for training, their contents are increasingly absorbed into model parameters, making them less effective for evaluating retrieval. We introduce SeedRG, a semi-synthetic benchmark generation pipeline that mitigates knowledge leakage and addresses the issue of benchmark aging. Starting from a seed benchmark dataset, SeedRG extracts a reasoning graph from question-context pairs to capture their underlying reasoning structure, and then generates new examples via type-constrained entity replacement. This process produces structurally similar but novel instances that are unlikely to exist in the model's parametric knowledge, while preserving the original reasoning patterns. To ensure quality, we incorporate two verification steps: (1) a reasoning-graph consistency check to maintain task difficulty, and (2) a knowledge-leakage filter to exclude instances answerable without retrieval.
format Preprint
id arxiv_https___arxiv_org_abs_2605_08838
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Generating Leakage-Free Benchmarks for Robust RAG Evaluation
Liu, Jiayi
Zhang, Jiaxing
Jin, Bowen
Neville, Jennifer
Computation and Language
Artificial Intelligence
Retrieval-augmented generation (RAG) is widely used to augment large language models (LLMs) with external knowledge. However, many benchmark datasets, designed to test RAG performance, comprise many questions that can already be answered from an LLM's parametric memory. This leads to unreliable evaluation. We refer to this phenomenon as knowledge leakage: cases where RAG tasks are solvable without retrieval. This issue worsens over time due to benchmark aging. As benchmarks are reused for training, their contents are increasingly absorbed into model parameters, making them less effective for evaluating retrieval. We introduce SeedRG, a semi-synthetic benchmark generation pipeline that mitigates knowledge leakage and addresses the issue of benchmark aging. Starting from a seed benchmark dataset, SeedRG extracts a reasoning graph from question-context pairs to capture their underlying reasoning structure, and then generates new examples via type-constrained entity replacement. This process produces structurally similar but novel instances that are unlikely to exist in the model's parametric knowledge, while preserving the original reasoning patterns. To ensure quality, we incorporate two verification steps: (1) a reasoning-graph consistency check to maintain task difficulty, and (2) a knowledge-leakage filter to exclude instances answerable without retrieval.
title Generating Leakage-Free Benchmarks for Robust RAG Evaluation
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2605.08838