Confidence-Aware Alignment Makes Reasoning LLMs More Reliable

Fuente: arXiv
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Main Authors: Chen, Kejia, Zhang, Jiawen, Wu, Yihong, Gao, Kewei, Lou, Jian, Feng, Zunlei, Song, Mingli, Jia, Ruoxi
Format: Preprint
Published: 2026
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author Chen, Kejia
Zhang, Jiawen
Wu, Yihong
Gao, Kewei
Lou, Jian
Feng, Zunlei
Song, Mingli
Jia, Ruoxi
author_facet Chen, Kejia
Zhang, Jiawen
Wu, Yihong
Gao, Kewei
Lou, Jian
Feng, Zunlei
Song, Mingli
Jia, Ruoxi
contents Large reasoning models often reach correct answers through flawed intermediate steps, creating a gap between final accuracy and reasoning reliability. Existing alignment strategies address this with external verifiers or massive sampling, limiting scalability. In this work, we introduce CASPO (Confidence-Aware Step-wise Preference Optimization), a framework that aligns token-level confidence with step-wise logical correctness through iterative Direct Preference Optimization, without training a separate reward model. During inference, we propose Confidence-aware Thought (CaT), which leverages this calibrated confidence to dynamically prune uncertain reasoning branches with negligible O(V) latency. Experiments across ten benchmarks and multiple model families show that CASPO consistently improves reasoning reliability and inference efficiency. CASPO scales to Qwen3-8B-Base and surpasses tree-search baselines on AIME'24 and AIME'25 without using reward-model data. We also release a step-wise dataset with confidence annotations to support fine-grained analysis of reasoning reliability. Code is available at https://github.com/Thecommonirin/CASPO.
format Preprint
id arxiv_https___arxiv_org_abs_2605_07353
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Confidence-Aware Alignment Makes Reasoning LLMs More Reliable
Chen, Kejia
Zhang, Jiawen
Wu, Yihong
Gao, Kewei
Lou, Jian
Feng, Zunlei
Song, Mingli
Jia, Ruoxi
Artificial Intelligence
Large reasoning models often reach correct answers through flawed intermediate steps, creating a gap between final accuracy and reasoning reliability. Existing alignment strategies address this with external verifiers or massive sampling, limiting scalability. In this work, we introduce CASPO (Confidence-Aware Step-wise Preference Optimization), a framework that aligns token-level confidence with step-wise logical correctness through iterative Direct Preference Optimization, without training a separate reward model. During inference, we propose Confidence-aware Thought (CaT), which leverages this calibrated confidence to dynamically prune uncertain reasoning branches with negligible O(V) latency. Experiments across ten benchmarks and multiple model families show that CASPO consistently improves reasoning reliability and inference efficiency. CASPO scales to Qwen3-8B-Base and surpasses tree-search baselines on AIME'24 and AIME'25 without using reward-model data. We also release a step-wise dataset with confidence annotations to support fine-grained analysis of reasoning reliability. Code is available at https://github.com/Thecommonirin/CASPO.
title Confidence-Aware Alignment Makes Reasoning LLMs More Reliable
topic Artificial Intelligence
url https://arxiv.org/abs/2605.07353