To Believe or Not to Believe Your LLM

Fuente: arXiv
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Auteurs principaux: Yadkori, Yasin Abbasi, Kuzborskij, Ilja, György, András, Szepesvári, Csaba
Format: Preprint
Publié: 2024
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author Yadkori, Yasin Abbasi
Kuzborskij, Ilja
György, András
Szepesvári, Csaba
author_facet Yadkori, Yasin Abbasi
Kuzborskij, Ilja
György, András
Szepesvári, Csaba
contents We explore uncertainty quantification in large language models (LLMs), with the goal to identify when uncertainty in responses given a query is large. We simultaneously consider both epistemic and aleatoric uncertainties, where the former comes from the lack of knowledge about the ground truth (such as about facts or the language), and the latter comes from irreducible randomness (such as multiple possible answers). In particular, we derive an information-theoretic metric that allows to reliably detect when only epistemic uncertainty is large, in which case the output of the model is unreliable. This condition can be computed based solely on the output of the model obtained simply by some special iterative prompting based on the previous responses. Such quantification, for instance, allows to detect hallucinations (cases when epistemic uncertainty is high) in both single- and multi-answer responses. This is in contrast to many standard uncertainty quantification strategies (such as thresholding the log-likelihood of a response) where hallucinations in the multi-answer case cannot be detected. We conduct a series of experiments which demonstrate the advantage of our formulation. Further, our investigations shed some light on how the probabilities assigned to a given output by an LLM can be amplified by iterative prompting, which might be of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2406_02543
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle To Believe or Not to Believe Your LLM
Yadkori, Yasin Abbasi
Kuzborskij, Ilja
György, András
Szepesvári, Csaba
Machine Learning
Artificial Intelligence
Computation and Language
We explore uncertainty quantification in large language models (LLMs), with the goal to identify when uncertainty in responses given a query is large. We simultaneously consider both epistemic and aleatoric uncertainties, where the former comes from the lack of knowledge about the ground truth (such as about facts or the language), and the latter comes from irreducible randomness (such as multiple possible answers). In particular, we derive an information-theoretic metric that allows to reliably detect when only epistemic uncertainty is large, in which case the output of the model is unreliable. This condition can be computed based solely on the output of the model obtained simply by some special iterative prompting based on the previous responses. Such quantification, for instance, allows to detect hallucinations (cases when epistemic uncertainty is high) in both single- and multi-answer responses. This is in contrast to many standard uncertainty quantification strategies (such as thresholding the log-likelihood of a response) where hallucinations in the multi-answer case cannot be detected. We conduct a series of experiments which demonstrate the advantage of our formulation. Further, our investigations shed some light on how the probabilities assigned to a given output by an LLM can be amplified by iterative prompting, which might be of independent interest.
title To Believe or Not to Believe Your LLM
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2406.02543