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Autori principali: Dakhmouche, Ramzi, Letellier, Adrien, Gorji, Hossein
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2510.04108
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author Dakhmouche, Ramzi
Letellier, Adrien
Gorji, Hossein
author_facet Dakhmouche, Ramzi
Letellier, Adrien
Gorji, Hossein
contents Effective Uncertainty Quantification (UQ) represents a key aspect for reliable deployment of Large Language Models (LLMs) in automated decision-making and beyond. Yet, for LLM generation with multiple choice structure, the state-of-the-art in UQ is still dominated by the naive baseline given by the maximum softmax score. To address this shortcoming, we demonstrate that taking a principled approach via Bayesian statistics leads to improved performance despite leveraging the simplest possible model, namely linear regression. More precisely, we propose to train multiple Bayesian linear models, each predicting the output of a layer given the output of the previous one. Based on the obtained layer-level posterior distributions, we infer the global uncertainty level of the LLM by identifying a sparse combination of distributional features, leading to an efficient UQ scheme. Numerical experiments on various LLMs show consistent improvement over state-of-the-art baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2510_04108
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Can Linear Probes Measure LLM Uncertainty?
Dakhmouche, Ramzi
Letellier, Adrien
Gorji, Hossein
Machine Learning
Numerical Analysis
Statistics Theory
Effective Uncertainty Quantification (UQ) represents a key aspect for reliable deployment of Large Language Models (LLMs) in automated decision-making and beyond. Yet, for LLM generation with multiple choice structure, the state-of-the-art in UQ is still dominated by the naive baseline given by the maximum softmax score. To address this shortcoming, we demonstrate that taking a principled approach via Bayesian statistics leads to improved performance despite leveraging the simplest possible model, namely linear regression. More precisely, we propose to train multiple Bayesian linear models, each predicting the output of a layer given the output of the previous one. Based on the obtained layer-level posterior distributions, we infer the global uncertainty level of the LLM by identifying a sparse combination of distributional features, leading to an efficient UQ scheme. Numerical experiments on various LLMs show consistent improvement over state-of-the-art baselines.
title Can Linear Probes Measure LLM Uncertainty?
topic Machine Learning
Numerical Analysis
Statistics Theory
url https://arxiv.org/abs/2510.04108