Bridging Internal Probability and Self-Consistency for Effective and Efficient LLM Reasoning

Fuente: arXiv
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Main Authors: Zhou, Zhi, Yuhao, Tan, Li, Zenan, Yao, Yuan, Guo, Lan-Zhe, Ma, Xiaoxing, Li, Yu-Feng
Format: Preprint
Published: 2025
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author Zhou, Zhi
Yuhao, Tan
Li, Zenan
Yao, Yuan
Guo, Lan-Zhe
Ma, Xiaoxing
Li, Yu-Feng
author_facet Zhou, Zhi
Yuhao, Tan
Li, Zenan
Yao, Yuan
Guo, Lan-Zhe
Ma, Xiaoxing
Li, Yu-Feng
contents Recent advancements in large language models (LLMs) have demonstrated remarkable reasoning capabilities. However, single-shot inference often yields unreliable results for complex reasoning tasks, leading researchers to explore multiple reasoning paths through methods such as perplexity and self-consistency. In this paper, we present the first theoretical error decomposition analysis of these techniques, breaking down their error into estimation error and model error. Our analysis reveals a fundamental trade-off: perplexity methods suffer from substantial model error due to the absence of a proper consistency function, while self-consistency exhibits high estimation error due to a slow error convergence rate. To overcome these limitations, we propose Reasoning-Pruning Perplexity Consistency (RPC). This approach combines Perplexity Consistency, which seamlessly integrates LLM perplexity with self-consistency, and Reasoning Pruning, which eliminates low-probability reasoning paths to effectively prevent the degeneration of estimation error reduction. Theoretical analysis demonstrates that RPC not only accelerates the convergence rate of estimation error to an exponential level but also holds strong potential for further reducing model error. Extensive empirical evaluations on seven benchmark datasets confirm that RPC can significantly improve reasoning performance, sample efficiency, and confidence reliability.
format Preprint
id arxiv_https___arxiv_org_abs_2502_00511
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bridging Internal Probability and Self-Consistency for Effective and Efficient LLM Reasoning
Zhou, Zhi
Yuhao, Tan
Li, Zenan
Yao, Yuan
Guo, Lan-Zhe
Ma, Xiaoxing
Li, Yu-Feng
Machine Learning
Artificial Intelligence
Computation and Language
Recent advancements in large language models (LLMs) have demonstrated remarkable reasoning capabilities. However, single-shot inference often yields unreliable results for complex reasoning tasks, leading researchers to explore multiple reasoning paths through methods such as perplexity and self-consistency. In this paper, we present the first theoretical error decomposition analysis of these techniques, breaking down their error into estimation error and model error. Our analysis reveals a fundamental trade-off: perplexity methods suffer from substantial model error due to the absence of a proper consistency function, while self-consistency exhibits high estimation error due to a slow error convergence rate. To overcome these limitations, we propose Reasoning-Pruning Perplexity Consistency (RPC). This approach combines Perplexity Consistency, which seamlessly integrates LLM perplexity with self-consistency, and Reasoning Pruning, which eliminates low-probability reasoning paths to effectively prevent the degeneration of estimation error reduction. Theoretical analysis demonstrates that RPC not only accelerates the convergence rate of estimation error to an exponential level but also holds strong potential for further reducing model error. Extensive empirical evaluations on seven benchmark datasets confirm that RPC can significantly improve reasoning performance, sample efficiency, and confidence reliability.
title Bridging Internal Probability and Self-Consistency for Effective and Efficient LLM Reasoning
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2502.00511