Self-Guided Process Reward Optimization with Redefined Step-wise Advantage for Process Reinforcement Learning

Fuente: arXiv
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Autores principales: Fei, Wu, Kong, Hao, Liang, Shuxian, Lin, Yang, Yang, Yibo, Tang, Jing, Chen, Lei, Hua, Xiansheng
Formato: Preprint
Publicado: 2025
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author Fei, Wu
Kong, Hao
Liang, Shuxian
Lin, Yang
Yang, Yibo
Tang, Jing
Chen, Lei
Hua, Xiansheng
author_facet Fei, Wu
Kong, Hao
Liang, Shuxian
Lin, Yang
Yang, Yibo
Tang, Jing
Chen, Lei
Hua, Xiansheng
contents Process Reinforcement Learning~(PRL) has demonstrated considerable potential in enhancing the reasoning capabilities of Large Language Models~(LLMs). However, introducing additional process reward models incurs substantial computational overhead, and there is no unified theoretical framework for process-level advantage estimation. To bridge this gap, we propose \textbf{S}elf-Guided \textbf{P}rocess \textbf{R}eward \textbf{O}ptimization~(\textbf{SPRO}), a novel framework that enables process-aware RL through two key innovations: (1) we first theoretically demonstrate that process rewards can be derived intrinsically from the policy model itself, and (2) we introduce well-defined cumulative process rewards and \textbf{M}asked \textbf{S}tep \textbf{A}dvantage (\textbf{MSA}), which facilitates rigorous step-wise action advantage estimation within shared-prompt sampling groups. Our experimental results demonstrate that SPRO outperforms vaniila GRPO with 3.4x higher training efficiency and a 17.5\% test accuracy improvement. Furthermore, SPRO maintains a stable and elevated policy entropy throughout training while reducing the average response length by approximately $1/3$, evidencing sufficient exploration and prevention of reward hacking. Notably, SPRO incurs no additional computational overhead compared to outcome-supervised RL methods such as GRPO, which benefit industrial implementation.
format Preprint
id arxiv_https___arxiv_org_abs_2507_01551
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Self-Guided Process Reward Optimization with Redefined Step-wise Advantage for Process Reinforcement Learning
Fei, Wu
Kong, Hao
Liang, Shuxian
Lin, Yang
Yang, Yibo
Tang, Jing
Chen, Lei
Hua, Xiansheng
Machine Learning
Artificial Intelligence
Computation and Language
Process Reinforcement Learning~(PRL) has demonstrated considerable potential in enhancing the reasoning capabilities of Large Language Models~(LLMs). However, introducing additional process reward models incurs substantial computational overhead, and there is no unified theoretical framework for process-level advantage estimation. To bridge this gap, we propose \textbf{S}elf-Guided \textbf{P}rocess \textbf{R}eward \textbf{O}ptimization~(\textbf{SPRO}), a novel framework that enables process-aware RL through two key innovations: (1) we first theoretically demonstrate that process rewards can be derived intrinsically from the policy model itself, and (2) we introduce well-defined cumulative process rewards and \textbf{M}asked \textbf{S}tep \textbf{A}dvantage (\textbf{MSA}), which facilitates rigorous step-wise action advantage estimation within shared-prompt sampling groups. Our experimental results demonstrate that SPRO outperforms vaniila GRPO with 3.4x higher training efficiency and a 17.5\% test accuracy improvement. Furthermore, SPRO maintains a stable and elevated policy entropy throughout training while reducing the average response length by approximately $1/3$, evidencing sufficient exploration and prevention of reward hacking. Notably, SPRO incurs no additional computational overhead compared to outcome-supervised RL methods such as GRPO, which benefit industrial implementation.
title Self-Guided Process Reward Optimization with Redefined Step-wise Advantage for Process Reinforcement Learning
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2507.01551