Scaling Flaws of Verifier-Guided Search in Mathematical Reasoning

Fuente: arXiv
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Main Authors: Yu, Fei, Li, Yingru, Wang, Benyou
Format: Preprint
Published: 2025
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author Yu, Fei
Li, Yingru
Wang, Benyou
author_facet Yu, Fei
Li, Yingru
Wang, Benyou
contents Large language models (LLMs) struggle with multi-step reasoning, where inference-time scaling has emerged as a promising strategy for performance improvement. Verifier-guided search outperforms repeated sampling when sample size is limited by selecting and prioritizing valid reasoning paths. However, we identify a critical limitation: scaling flaws, prevalent across different models (Mistral 7B and DeepSeekMath 7B), benchmarks (GSM8K and MATH), and verifiers (outcome value models and process reward models). As sample size increases, verifier-guided search exhibits diminishing advantages and eventually underperforms repeated sampling. Our analysis attributes this to verifier failures, where imperfect verifiers misrank candidates and erroneously prune all valid paths. These issues are further exacerbated in challenging and out-of-distribution problems, restricting search effectiveness. To mitigate verifier failures, we explore reducing reliance on verifiers and conduct preliminary investigations using two simple methods. Our findings reveal fundamental limitations in verifier-guided search and suggest future directions.
format Preprint
id arxiv_https___arxiv_org_abs_2502_00271
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Scaling Flaws of Verifier-Guided Search in Mathematical Reasoning
Yu, Fei
Li, Yingru
Wang, Benyou
Computation and Language
Large language models (LLMs) struggle with multi-step reasoning, where inference-time scaling has emerged as a promising strategy for performance improvement. Verifier-guided search outperforms repeated sampling when sample size is limited by selecting and prioritizing valid reasoning paths. However, we identify a critical limitation: scaling flaws, prevalent across different models (Mistral 7B and DeepSeekMath 7B), benchmarks (GSM8K and MATH), and verifiers (outcome value models and process reward models). As sample size increases, verifier-guided search exhibits diminishing advantages and eventually underperforms repeated sampling. Our analysis attributes this to verifier failures, where imperfect verifiers misrank candidates and erroneously prune all valid paths. These issues are further exacerbated in challenging and out-of-distribution problems, restricting search effectiveness. To mitigate verifier failures, we explore reducing reliance on verifiers and conduct preliminary investigations using two simple methods. Our findings reveal fundamental limitations in verifier-guided search and suggest future directions.
title Scaling Flaws of Verifier-Guided Search in Mathematical Reasoning
topic Computation and Language
url https://arxiv.org/abs/2502.00271