Don't Throw Away Your Beams: Improving Consistency-based Uncertainties in LLMs via Beam Search

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Fadeeva, Ekaterina, Goloburda, Maiya, Rubashevskii, Aleksandr, Vashurin, Roman, Shelmanov, Artem, Nakov, Preslav, Sachan, Mrinmaya, Panov, Maxim
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914538434068480
author Fadeeva, Ekaterina
Goloburda, Maiya
Rubashevskii, Aleksandr
Vashurin, Roman
Shelmanov, Artem
Nakov, Preslav
Sachan, Mrinmaya
Panov, Maxim
author_facet Fadeeva, Ekaterina
Goloburda, Maiya
Rubashevskii, Aleksandr
Vashurin, Roman
Shelmanov, Artem
Nakov, Preslav
Sachan, Mrinmaya
Panov, Maxim
contents Consistency-based methods have emerged as an effective approach to uncertainty quantification (UQ) in large language models. These methods typically rely on several generations obtained via multinomial sampling, measuring their agreement level. However, in short-form QA, multinomial sampling is prone to producing duplicates due to peaked distributions, and its stochasticity introduces considerable variance in uncertainty estimates across runs. We introduce a new family of methods that employ beam search to generate candidates for consistency-based UQ, yielding improved performance and reduced variance compared to multinomial sampling. We also provide a theoretical lower bound on the beam set probability mass under which beam search achieves a smaller error than multinomial sampling. We empirically evaluate our approach on six QA datasets and find that its consistent improvements over multinomial sampling lead to state-of-the-art UQ performance.
format Preprint
id arxiv_https___arxiv_org_abs_2512_09538
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Don't Throw Away Your Beams: Improving Consistency-based Uncertainties in LLMs via Beam Search
Fadeeva, Ekaterina
Goloburda, Maiya
Rubashevskii, Aleksandr
Vashurin, Roman
Shelmanov, Artem
Nakov, Preslav
Sachan, Mrinmaya
Panov, Maxim
Machine Learning
Computation and Language
Consistency-based methods have emerged as an effective approach to uncertainty quantification (UQ) in large language models. These methods typically rely on several generations obtained via multinomial sampling, measuring their agreement level. However, in short-form QA, multinomial sampling is prone to producing duplicates due to peaked distributions, and its stochasticity introduces considerable variance in uncertainty estimates across runs. We introduce a new family of methods that employ beam search to generate candidates for consistency-based UQ, yielding improved performance and reduced variance compared to multinomial sampling. We also provide a theoretical lower bound on the beam set probability mass under which beam search achieves a smaller error than multinomial sampling. We empirically evaluate our approach on six QA datasets and find that its consistent improvements over multinomial sampling lead to state-of-the-art UQ performance.
title Don't Throw Away Your Beams: Improving Consistency-based Uncertainties in LLMs via Beam Search
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2512.09538