A Gradient Perspective on RLVR Stability and Winner-Advantage Policy Optimization

Prasanth Yss, Zhichen Ren, Rasa Hosseinzadeh, Ilan Gofman, Yuqi Chen, Zhaoyan Liu, Guangwei Yu, Jesse C. Cresswell, Satya Krishna Gorti


Abstract
Reinforcement learning with verifiable rewards (RLVR) improves language-model reasoning, but GRPO-style optimization remains prone to collapse. We analyse this instability through token-level gradient dynamics, deriving a taxonomy that predicts how updates affect next-token probabilities and entropy. The taxonomy shows that stability depends jointly on the advantage sign and token distribution under the current policy. Motivated by this finding, we propose Winner Advantage Policy Optimization (WAPO), a simple online clipped policy-gradient objective that updates only on positive-advantage completions. Across mathematical reasoning and multi-hop QA benchmarks, WAPO improves training stability and matches or outperforms baselines across multiple model families. Full code can be found at https://github.com/layer6ai-labs/wapo.
Anthology ID:
2026.emnlp-main.2371
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
53806–53826
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URL:
https://aclanthology.org/2026.emnlp-main.2371/
DOI:
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Cite (ACL):
Prasanth Yss, Zhichen Ren, Rasa Hosseinzadeh, Ilan Gofman, Yuqi Chen, Zhaoyan Liu, Guangwei Yu, Jesse C. Cresswell, and Satya Krishna Gorti. 2026. A Gradient Perspective on RLVR Stability and Winner-Advantage Policy Optimization. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 53806–53826, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
A Gradient Perspective on RLVR Stability and Winner-Advantage Policy Optimization (Yss et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2371.pdf