Fair RAG: End-to-End Fairness Across Retrieval and Generation

Farsheed Haque, Zhe Fu, Ramit Aditya, Depeng Xu, Xi Niu


Abstract
Large Language Models (LLMs) used in Retrieval-Augmented Generation (RAG) can amplify demographic bias: retrievers may surface skewed context and generators can propagate that skew into decisions. Prior work typically treats fairness in retrieval or generation in isolation, leaving end-to-end fairness in RAG underexplored. We propose a post-hoc pipeline that jointly controls both stages: (i) a Fair Greedy Reranker (FGR) that builds prefix-balanced slates toward a target group mix; (ii) a Residual Slate Bias Estimator (RSBE) using signed, prefix-sensitive NDKL to quantify remaining skew; and (iii) Confidence-Gated Logit Calibration (CGLC) that converts the residual signal into small and margin-focused logit corrections without retraining. On an occupation classification task, our approach reduces retriever-side skew (lowest NDKL among baselines for both dense and sparse retrievers) and achieves the lowest generator-side disparity (e.g., Risk Difference) while largely preserving utility. The same calibration can be tuned to alternative fairness criteria (e.g., Equal Opportunity) with minimal utility loss.
Anthology ID:
2026.findings-acl.1358
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
27256–27270
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1358/
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Bibkey:
Cite (ACL):
Farsheed Haque, Zhe Fu, Ramit Aditya, Depeng Xu, and Xi Niu. 2026. Fair RAG: End-to-End Fairness Across Retrieval and Generation. In Findings of the Association for Computational Linguistics: ACL 2026, pages 27256–27270, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Fair RAG: End-to-End Fairness Across Retrieval and Generation (Haque et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1358.pdf
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