Mitigating LLM Hallucinations via Conformal Abstention

Fuente: arXiv
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Autori principali: Yadkori, Yasin Abbasi, Kuzborskij, Ilja, Stutz, David, György, András, Fisch, Adam, Doucet, Arnaud, Beloshapka, Iuliya, Weng, Wei-Hung, Yang, Yao-Yuan, Szepesvári, Csaba, Cemgil, Ali Taylan, Tomasev, Nenad
Natura: Preprint
Pubblicazione: 2024
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author Yadkori, Yasin Abbasi
Kuzborskij, Ilja
Stutz, David
György, András
Fisch, Adam
Doucet, Arnaud
Beloshapka, Iuliya
Weng, Wei-Hung
Yang, Yao-Yuan
Szepesvári, Csaba
Cemgil, Ali Taylan
Tomasev, Nenad
author_facet Yadkori, Yasin Abbasi
Kuzborskij, Ilja
Stutz, David
György, András
Fisch, Adam
Doucet, Arnaud
Beloshapka, Iuliya
Weng, Wei-Hung
Yang, Yao-Yuan
Szepesvári, Csaba
Cemgil, Ali Taylan
Tomasev, Nenad
contents We develop a principled procedure for determining when a large language model (LLM) should abstain from responding (e.g., by saying "I don't know") in a general domain, instead of resorting to possibly "hallucinating" a non-sensical or incorrect answer. Building on earlier approaches that use self-consistency as a more reliable measure of model confidence, we propose using the LLM itself to self-evaluate the similarity between each of its sampled responses for a given query. We then further leverage conformal prediction techniques to develop an abstention procedure that benefits from rigorous theoretical guarantees on the hallucination rate (error rate). Experimentally, our resulting conformal abstention method reliably bounds the hallucination rate on various closed-book, open-domain generative question answering datasets, while also maintaining a significantly less conservative abstention rate on a dataset with long responses (Temporal Sequences) compared to baselines using log-probability scores to quantify uncertainty, while achieveing comparable performance on a dataset with short answers (TriviaQA). To evaluate the experiments automatically, one needs to determine if two responses are equivalent given a question. Following standard practice, we use a thresholded similarity function to determine if two responses match, but also provide a method for calibrating the threshold based on conformal prediction, with theoretical guarantees on the accuracy of the match prediction, which might be of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2405_01563
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mitigating LLM Hallucinations via Conformal Abstention
Yadkori, Yasin Abbasi
Kuzborskij, Ilja
Stutz, David
György, András
Fisch, Adam
Doucet, Arnaud
Beloshapka, Iuliya
Weng, Wei-Hung
Yang, Yao-Yuan
Szepesvári, Csaba
Cemgil, Ali Taylan
Tomasev, Nenad
Machine Learning
Artificial Intelligence
Computation and Language
We develop a principled procedure for determining when a large language model (LLM) should abstain from responding (e.g., by saying "I don't know") in a general domain, instead of resorting to possibly "hallucinating" a non-sensical or incorrect answer. Building on earlier approaches that use self-consistency as a more reliable measure of model confidence, we propose using the LLM itself to self-evaluate the similarity between each of its sampled responses for a given query. We then further leverage conformal prediction techniques to develop an abstention procedure that benefits from rigorous theoretical guarantees on the hallucination rate (error rate). Experimentally, our resulting conformal abstention method reliably bounds the hallucination rate on various closed-book, open-domain generative question answering datasets, while also maintaining a significantly less conservative abstention rate on a dataset with long responses (Temporal Sequences) compared to baselines using log-probability scores to quantify uncertainty, while achieveing comparable performance on a dataset with short answers (TriviaQA). To evaluate the experiments automatically, one needs to determine if two responses are equivalent given a question. Following standard practice, we use a thresholded similarity function to determine if two responses match, but also provide a method for calibrating the threshold based on conformal prediction, with theoretical guarantees on the accuracy of the match prediction, which might be of independent interest.
title Mitigating LLM Hallucinations via Conformal Abstention
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2405.01563