Verify when Uncertain: Beyond Self-Consistency in Black Box Hallucination Detection

Fuente: arXiv
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Autori principali: Xue, Yihao, Greenewald, Kristjan, Mroueh, Youssef, Mirzasoleiman, Baharan
Natura: Preprint
Pubblicazione: 2025
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author Xue, Yihao
Greenewald, Kristjan
Mroueh, Youssef
Mirzasoleiman, Baharan
author_facet Xue, Yihao
Greenewald, Kristjan
Mroueh, Youssef
Mirzasoleiman, Baharan
contents Large Language Models (LLMs) suffer from hallucination problems, which hinder their reliability in sensitive applications. In the black-box setting, several self-consistency-based techniques have been proposed for hallucination detection. We empirically study these techniques and show that they achieve performance close to that of a supervised (still black-box) oracle, suggesting little room for improvement within this paradigm. To address this limitation, we explore cross-model consistency checking between the target model and an additional verifier LLM. With this extra information, we observe improved oracle performance compared to purely self-consistency-based methods. We then propose a budget-friendly, two-stage detection algorithm that calls the verifier model only for a subset of cases. It dynamically switches between self-consistency and cross-consistency based on an uncertainty interval of the self-consistency classifier. We provide a geometric interpretation of consistency-based hallucination detection methods through the lens of kernel mean embeddings, offering deeper theoretical insights. Extensive experiments show that this approach maintains high detection performance while significantly reducing computational cost.
format Preprint
id arxiv_https___arxiv_org_abs_2502_15845
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Verify when Uncertain: Beyond Self-Consistency in Black Box Hallucination Detection
Xue, Yihao
Greenewald, Kristjan
Mroueh, Youssef
Mirzasoleiman, Baharan
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) suffer from hallucination problems, which hinder their reliability in sensitive applications. In the black-box setting, several self-consistency-based techniques have been proposed for hallucination detection. We empirically study these techniques and show that they achieve performance close to that of a supervised (still black-box) oracle, suggesting little room for improvement within this paradigm. To address this limitation, we explore cross-model consistency checking between the target model and an additional verifier LLM. With this extra information, we observe improved oracle performance compared to purely self-consistency-based methods. We then propose a budget-friendly, two-stage detection algorithm that calls the verifier model only for a subset of cases. It dynamically switches between self-consistency and cross-consistency based on an uncertainty interval of the self-consistency classifier. We provide a geometric interpretation of consistency-based hallucination detection methods through the lens of kernel mean embeddings, offering deeper theoretical insights. Extensive experiments show that this approach maintains high detection performance while significantly reducing computational cost.
title Verify when Uncertain: Beyond Self-Consistency in Black Box Hallucination Detection
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2502.15845