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Autori principali: Ciosek, Kamil, Felicioni, Nicolò, Ghiassian, Sina
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2504.03579
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author Ciosek, Kamil
Felicioni, Nicolò
Ghiassian, Sina
author_facet Ciosek, Kamil
Felicioni, Nicolò
Ghiassian, Sina
contents Detecting whether an LLM hallucinates is an important research challenge. One promising way of doing so is to estimate the semantic entropy (Farquhar et al., 2024) of the distribution of generated sequences. We propose a new algorithm for doing that, with two main advantages. First, due to us taking the Bayesian approach, we achieve a much better quality of semantic entropy estimates for a given budget of samples from the LLM. Second, we are able to tune the number of samples adaptively so that `harder' contexts receive more samples. We demonstrate empirically that our approach systematically beats the baselines, requiring only 53% of samples used by Farquhar et al. (2024) to achieve the same quality of hallucination detection as measured by AUROC. Moreover, quite counterintuitively, our estimator is useful even with just one sample from the LLM.
format Preprint
id arxiv_https___arxiv_org_abs_2504_03579
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hallucination Detection on a Budget: Efficient Bayesian Estimation of Semantic Entropy
Ciosek, Kamil
Felicioni, Nicolò
Ghiassian, Sina
Machine Learning
Detecting whether an LLM hallucinates is an important research challenge. One promising way of doing so is to estimate the semantic entropy (Farquhar et al., 2024) of the distribution of generated sequences. We propose a new algorithm for doing that, with two main advantages. First, due to us taking the Bayesian approach, we achieve a much better quality of semantic entropy estimates for a given budget of samples from the LLM. Second, we are able to tune the number of samples adaptively so that `harder' contexts receive more samples. We demonstrate empirically that our approach systematically beats the baselines, requiring only 53% of samples used by Farquhar et al. (2024) to achieve the same quality of hallucination detection as measured by AUROC. Moreover, quite counterintuitively, our estimator is useful even with just one sample from the LLM.
title Hallucination Detection on a Budget: Efficient Bayesian Estimation of Semantic Entropy
topic Machine Learning
url https://arxiv.org/abs/2504.03579