Open Rubric System: Scaling Reinforcement Learning with Pairwise Adaptive Rubric

Fuente: arXiv
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Auteurs principaux: Jia, Ruipeng, Yang, Yunyi, Wu, Yuxin, Gai, Yongbo, Tao, Siyuan, Zhou, Mengyu, Lin, Jianhe, Jiang, Xiaoxi, Jiang, Guanjun
Format: Preprint
Publié: 2026
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author Jia, Ruipeng
Yang, Yunyi
Wu, Yuxin
Gai, Yongbo
Tao, Siyuan
Zhou, Mengyu
Lin, Jianhe
Jiang, Xiaoxi
Jiang, Guanjun
author_facet Jia, Ruipeng
Yang, Yunyi
Wu, Yuxin
Gai, Yongbo
Tao, Siyuan
Zhou, Mengyu
Lin, Jianhe
Jiang, Xiaoxi
Jiang, Guanjun
contents Scalar reward models compress multi-dimensional human preferences into a single opaque score, creating an information bottleneck that often leads to brittleness and reward hacking in open-ended alignment. We argue that robust alignment for non-verifiable tasks is fundamentally a principle generalization problem: reward should not be a learned function internalized into a judge, but an explicit reasoning process executed under inspectable principles. To operationalize this view, we present the Open Rubric System (OpenRS), a plug-and-play, rubrics-based LLM-as-a-Judge framework built around Pairwise Adaptive Meta-Rubrics (PAMR) and lightweight Pointwise Verifiable Rubrics (PVRs), which provide both hard-constraint guardrails and verifiable reward components when ground-truth or programmatic checks are available. OpenRS uses an explicit meta-rubric -- a constitution-like specification that governs how rubrics are instantiated, weighted, and enforced -- and instantiates adaptive rubrics on the fly by conditioning on the semantic differences between two candidate responses. It then performs criterion-wise pairwise comparisons and aggregates criterion-level preferences externally, avoiding pointwise weighted scalarization while improving discriminability in open-ended settings. To keep principles consistent yet editable across various domains, we introduce a two-level meta-rubric refinement pipeline (automated evolutionary refinement for general principles and a reproducible human-in-the-loop procedure for domain principles), complemented with pointwise verifiable rubrics that act as both guardrails against degenerate behaviors and a source of verifiable reward for objective sub-tasks. Finally, we instantiate OpenRS as reward supervision in pairwise RL training.
format Preprint
id arxiv_https___arxiv_org_abs_2602_14069
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Open Rubric System: Scaling Reinforcement Learning with Pairwise Adaptive Rubric
Jia, Ruipeng
Yang, Yunyi
Wu, Yuxin
Gai, Yongbo
Tao, Siyuan
Zhou, Mengyu
Lin, Jianhe
Jiang, Xiaoxi
Jiang, Guanjun
Computation and Language
Scalar reward models compress multi-dimensional human preferences into a single opaque score, creating an information bottleneck that often leads to brittleness and reward hacking in open-ended alignment. We argue that robust alignment for non-verifiable tasks is fundamentally a principle generalization problem: reward should not be a learned function internalized into a judge, but an explicit reasoning process executed under inspectable principles. To operationalize this view, we present the Open Rubric System (OpenRS), a plug-and-play, rubrics-based LLM-as-a-Judge framework built around Pairwise Adaptive Meta-Rubrics (PAMR) and lightweight Pointwise Verifiable Rubrics (PVRs), which provide both hard-constraint guardrails and verifiable reward components when ground-truth or programmatic checks are available. OpenRS uses an explicit meta-rubric -- a constitution-like specification that governs how rubrics are instantiated, weighted, and enforced -- and instantiates adaptive rubrics on the fly by conditioning on the semantic differences between two candidate responses. It then performs criterion-wise pairwise comparisons and aggregates criterion-level preferences externally, avoiding pointwise weighted scalarization while improving discriminability in open-ended settings. To keep principles consistent yet editable across various domains, we introduce a two-level meta-rubric refinement pipeline (automated evolutionary refinement for general principles and a reproducible human-in-the-loop procedure for domain principles), complemented with pointwise verifiable rubrics that act as both guardrails against degenerate behaviors and a source of verifiable reward for objective sub-tasks. Finally, we instantiate OpenRS as reward supervision in pairwise RL training.
title Open Rubric System: Scaling Reinforcement Learning with Pairwise Adaptive Rubric
topic Computation and Language
url https://arxiv.org/abs/2602.14069