Improving Uncertainty Quantification in Large Language Models via Semantic Embeddings

Fuente: arXiv
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Auteurs principaux: Grewal, Yashvir S., Bonilla, Edwin V., Bui, Thang D.
Format: Preprint
Publié: 2024
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author Grewal, Yashvir S.
Bonilla, Edwin V.
Bui, Thang D.
author_facet Grewal, Yashvir S.
Bonilla, Edwin V.
Bui, Thang D.
contents Accurately quantifying uncertainty in large language models (LLMs) is crucial for their reliable deployment, especially in high-stakes applications. Current state-of-the-art methods for measuring semantic uncertainty in LLMs rely on strict bidirectional entailment criteria between multiple generated responses and also depend on sequence likelihoods. While effective, these approaches often overestimate uncertainty due to their sensitivity to minor wording differences, additional correct information, and non-important words in the sequence. We propose a novel approach that leverages semantic embeddings to achieve smoother and more robust estimation of semantic uncertainty in LLMs. By capturing semantic similarities without depending on sequence likelihoods, our method inherently reduces any biases introduced by irrelevant words in the answers. Furthermore, we introduce an amortised version of our approach by explicitly modelling semantics as latent variables in a joint probabilistic model. This allows for uncertainty estimation in the embedding space with a single forward pass, significantly reducing computational overhead compared to existing multi-pass methods. Experiments across multiple question-answering datasets and frontier LLMs demonstrate that our embedding-based methods provide more accurate and nuanced uncertainty quantification than traditional approaches.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22685
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improving Uncertainty Quantification in Large Language Models via Semantic Embeddings
Grewal, Yashvir S.
Bonilla, Edwin V.
Bui, Thang D.
Machine Learning
Artificial Intelligence
Computation and Language
Accurately quantifying uncertainty in large language models (LLMs) is crucial for their reliable deployment, especially in high-stakes applications. Current state-of-the-art methods for measuring semantic uncertainty in LLMs rely on strict bidirectional entailment criteria between multiple generated responses and also depend on sequence likelihoods. While effective, these approaches often overestimate uncertainty due to their sensitivity to minor wording differences, additional correct information, and non-important words in the sequence. We propose a novel approach that leverages semantic embeddings to achieve smoother and more robust estimation of semantic uncertainty in LLMs. By capturing semantic similarities without depending on sequence likelihoods, our method inherently reduces any biases introduced by irrelevant words in the answers. Furthermore, we introduce an amortised version of our approach by explicitly modelling semantics as latent variables in a joint probabilistic model. This allows for uncertainty estimation in the embedding space with a single forward pass, significantly reducing computational overhead compared to existing multi-pass methods. Experiments across multiple question-answering datasets and frontier LLMs demonstrate that our embedding-based methods provide more accurate and nuanced uncertainty quantification than traditional approaches.
title Improving Uncertainty Quantification in Large Language Models via Semantic Embeddings
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2410.22685