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Main Authors: Yu, Bin, Wang, Xinming, Lian, Shijie, Li, Haotian, Wu, Changti, Hu, Ruina, Wang, Bailing, Wei, Yuliang, Chen, Kai
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.16449
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author Yu, Bin
Wang, Xinming
Lian, Shijie
Li, Haotian
Wu, Changti
Hu, Ruina
Wang, Bailing
Wei, Yuliang
Chen, Kai
author_facet Yu, Bin
Wang, Xinming
Lian, Shijie
Li, Haotian
Wu, Changti
Hu, Ruina
Wang, Bailing
Wei, Yuliang
Chen, Kai
contents Large language models (LLMs) have shown remarkable progress in complex reasoning tasks, largely enabled by test-time scaling (TTS) paradigms that allocate additional compute during inference. Among these, external TTS (particularly the Best-of-N selection paradigm) yields scalable performance improvements by selecting from multiple independently generated reasoning trajectories. However, this approach faces key limitations: (i) the high computational overhead of deploying process reward models, (ii) the underutilization of the LLM's intrinsic latent representations. We introduce TrajSelector, an efficient and effective Best-of-N framework that exploit the hidden states in the sampler LLM for process-level scoring. A lightweight verifier (with only 0.6B parameters) evaluates the quality of step-wise trajectory, and then aggregates these scores to identify the optimal reasoning trajectory. Our framework employs a fully data-driven, end-to-end training recipe that eliminates reliance on massive step-level annotations. Experiential results across five benchmarks demonstrate that TrajSelector delivers consistent performance gains. In Best-of-32 settings, it surpasses majority voting by 4.61% accuracy and outperforms existing process reward models by 4.31% to 12.21%, all while maintaining lower inference costs.
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id arxiv_https___arxiv_org_abs_2510_16449
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle TrajSelector: Harnessing Latent Representations for Efficient and Effective Best-of-N in Large Reasoning Model
Yu, Bin
Wang, Xinming
Lian, Shijie
Li, Haotian
Wu, Changti
Hu, Ruina
Wang, Bailing
Wei, Yuliang
Chen, Kai
Computation and Language
Large language models (LLMs) have shown remarkable progress in complex reasoning tasks, largely enabled by test-time scaling (TTS) paradigms that allocate additional compute during inference. Among these, external TTS (particularly the Best-of-N selection paradigm) yields scalable performance improvements by selecting from multiple independently generated reasoning trajectories. However, this approach faces key limitations: (i) the high computational overhead of deploying process reward models, (ii) the underutilization of the LLM's intrinsic latent representations. We introduce TrajSelector, an efficient and effective Best-of-N framework that exploit the hidden states in the sampler LLM for process-level scoring. A lightweight verifier (with only 0.6B parameters) evaluates the quality of step-wise trajectory, and then aggregates these scores to identify the optimal reasoning trajectory. Our framework employs a fully data-driven, end-to-end training recipe that eliminates reliance on massive step-level annotations. Experiential results across five benchmarks demonstrate that TrajSelector delivers consistent performance gains. In Best-of-32 settings, it surpasses majority voting by 4.61% accuracy and outperforms existing process reward models by 4.31% to 12.21%, all while maintaining lower inference costs.
title TrajSelector: Harnessing Latent Representations for Efficient and Effective Best-of-N in Large Reasoning Model
topic Computation and Language
url https://arxiv.org/abs/2510.16449