Scalable Best-of-N Selection for Large Language Models via Self-Certainty

Fuente: arXiv
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Auteurs principaux: Kang, Zhewei, Zhao, Xuandong, Song, Dawn
Format: Preprint
Publié: 2025
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author Kang, Zhewei
Zhao, Xuandong
Song, Dawn
author_facet Kang, Zhewei
Zhao, Xuandong
Song, Dawn
contents Best-of-N selection is a key technique for improving the reasoning performance of Large Language Models (LLMs) through increased test-time computation. Current state-of-the-art methods often employ computationally intensive reward models for response evaluation and selection. Reward-free alternatives, like self-consistency and universal self-consistency, are limited in their ability to handle open-ended generation tasks or scale effectively. To address these limitations, we propose self-certainty, a novel and efficient metric that leverages the inherent probability distribution of LLM outputs to estimate response quality without requiring external reward models. We hypothesize that higher distributional self-certainty, aggregated across multiple samples, correlates with improved response accuracy, as it reflects greater confidence in the generated output. Through extensive experiments on various reasoning tasks, we demonstrate that self-certainty (1) scales effectively with increasing sample size N, akin to reward models but without the computational overhead; (2) complements chain-of-thought, improving reasoning performance beyond greedy decoding; and (3) generalizes to open-ended tasks where traditional self-consistency methods fall short. Our findings establish self-certainty as a practical and efficient way for improving LLM reasoning capabilities. The code is available at https://github.com/backprop07/Self-Certainty
format Preprint
id arxiv_https___arxiv_org_abs_2502_18581
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Scalable Best-of-N Selection for Large Language Models via Self-Certainty
Kang, Zhewei
Zhao, Xuandong
Song, Dawn
Computation and Language
Artificial Intelligence
Machine Learning
Best-of-N selection is a key technique for improving the reasoning performance of Large Language Models (LLMs) through increased test-time computation. Current state-of-the-art methods often employ computationally intensive reward models for response evaluation and selection. Reward-free alternatives, like self-consistency and universal self-consistency, are limited in their ability to handle open-ended generation tasks or scale effectively. To address these limitations, we propose self-certainty, a novel and efficient metric that leverages the inherent probability distribution of LLM outputs to estimate response quality without requiring external reward models. We hypothesize that higher distributional self-certainty, aggregated across multiple samples, correlates with improved response accuracy, as it reflects greater confidence in the generated output. Through extensive experiments on various reasoning tasks, we demonstrate that self-certainty (1) scales effectively with increasing sample size N, akin to reward models but without the computational overhead; (2) complements chain-of-thought, improving reasoning performance beyond greedy decoding; and (3) generalizes to open-ended tasks where traditional self-consistency methods fall short. Our findings establish self-certainty as a practical and efficient way for improving LLM reasoning capabilities. The code is available at https://github.com/backprop07/Self-Certainty
title Scalable Best-of-N Selection for Large Language Models via Self-Certainty
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2502.18581