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Main Authors: Zhang, Pinyi, Lin, Ting-En, Wu, Yuchuan, Chen, Jingyang, Wang, Zongqi, Yang, Hua, Xu, Ze, Huang, Fei, Zhang, Kai, Li, Yongbin
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.12116
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author Zhang, Pinyi
Lin, Ting-En
Wu, Yuchuan
Chen, Jingyang
Wang, Zongqi
Yang, Hua
Xu, Ze
Huang, Fei
Zhang, Kai
Li, Yongbin
author_facet Zhang, Pinyi
Lin, Ting-En
Wu, Yuchuan
Chen, Jingyang
Wang, Zongqi
Yang, Hua
Xu, Ze
Huang, Fei
Zhang, Kai
Li, Yongbin
contents Personalized alignment of large language models seeks to adapt responses to individual user preferences, typically via reinforcement learning. A key challenge is obtaining accurate, user-specific reward signals in open-ended scenarios. Existing personalized reward models face two persistent limitations: (1) oversimplifying diverse, scenario-specific preferences into a small, fixed set of evaluation principles, and (2) struggling with generalization to new users with limited feedback. To this end, we propose P-GenRM, the first Personalized Generative Reward Model with test-time user-based scaling. P-GenRM transforms preference signals into structured evaluation chains that derive adaptive personas and scoring rubrics across various scenarios. It further clusters users into User Prototypes and introduces a dual-granularity scaling mechanism: at the individual level, it adaptively scales and aggregates each user's scoring scheme; at the prototype level, it incorporates preferences from similar users. This design mitigates noise in inferred preferences and enhances generalization to unseen users through prototype-based transfer. Empirical results show that P-GenRM achieves state-of-the-art results on widely-used personalized reward model benchmarks, with an average improvement of 2.31%, and demonstrates strong generalization on an out-of-distribution dataset. Notably, Test-time User-based scaling provides an additional 3% boost, demonstrating stronger personalized alignment with test-time scalability.
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id arxiv_https___arxiv_org_abs_2602_12116
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publishDate 2026
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spellingShingle P-GenRM: Personalized Generative Reward Model with Test-time User-based Scaling
Zhang, Pinyi
Lin, Ting-En
Wu, Yuchuan
Chen, Jingyang
Wang, Zongqi
Yang, Hua
Xu, Ze
Huang, Fei
Zhang, Kai
Li, Yongbin
Computation and Language
Personalized alignment of large language models seeks to adapt responses to individual user preferences, typically via reinforcement learning. A key challenge is obtaining accurate, user-specific reward signals in open-ended scenarios. Existing personalized reward models face two persistent limitations: (1) oversimplifying diverse, scenario-specific preferences into a small, fixed set of evaluation principles, and (2) struggling with generalization to new users with limited feedback. To this end, we propose P-GenRM, the first Personalized Generative Reward Model with test-time user-based scaling. P-GenRM transforms preference signals into structured evaluation chains that derive adaptive personas and scoring rubrics across various scenarios. It further clusters users into User Prototypes and introduces a dual-granularity scaling mechanism: at the individual level, it adaptively scales and aggregates each user's scoring scheme; at the prototype level, it incorporates preferences from similar users. This design mitigates noise in inferred preferences and enhances generalization to unseen users through prototype-based transfer. Empirical results show that P-GenRM achieves state-of-the-art results on widely-used personalized reward model benchmarks, with an average improvement of 2.31%, and demonstrates strong generalization on an out-of-distribution dataset. Notably, Test-time User-based scaling provides an additional 3% boost, demonstrating stronger personalized alignment with test-time scalability.
title P-GenRM: Personalized Generative Reward Model with Test-time User-based Scaling
topic Computation and Language
url https://arxiv.org/abs/2602.12116