Rethinking Hallucinations: Correctness, Consistency, and Prompt Multiplicity

Fuente: arXiv
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Main Authors: Ganesh, Prakhar, Shokri, Reza, Farnadi, Golnoosh
Format: Preprint
Published: 2026
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author Ganesh, Prakhar
Shokri, Reza
Farnadi, Golnoosh
author_facet Ganesh, Prakhar
Shokri, Reza
Farnadi, Golnoosh
contents Large language models (LLMs) are known to "hallucinate" by generating false or misleading outputs. Hallucinations pose various harms, from erosion of trust to widespread misinformation. Existing hallucination evaluation, however, focuses only on correctness and often overlooks consistency, necessary to distinguish and address these harms. To bridge this gap, we introduce prompt multiplicity, a framework for quantifying consistency in LLM evaluations. Our analysis reveals significant multiplicity (over 50% inconsistency in benchmarks like Med-HALT), suggesting that hallucination-related harms have been severely misunderstood. Furthermore, we study the role of consistency in hallucination detection and mitigation. We find that: (a) detection techniques detect consistency, not correctness, and (b) mitigation techniques like RAG, while beneficial, can introduce additional inconsistencies. By integrating prompt multiplicity into hallucination evaluation, we provide an improved framework of potential harms and uncover critical limitations in current detection and mitigation strategies.
format Preprint
id arxiv_https___arxiv_org_abs_2602_00723
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rethinking Hallucinations: Correctness, Consistency, and Prompt Multiplicity
Ganesh, Prakhar
Shokri, Reza
Farnadi, Golnoosh
Machine Learning
Artificial Intelligence
Large language models (LLMs) are known to "hallucinate" by generating false or misleading outputs. Hallucinations pose various harms, from erosion of trust to widespread misinformation. Existing hallucination evaluation, however, focuses only on correctness and often overlooks consistency, necessary to distinguish and address these harms. To bridge this gap, we introduce prompt multiplicity, a framework for quantifying consistency in LLM evaluations. Our analysis reveals significant multiplicity (over 50% inconsistency in benchmarks like Med-HALT), suggesting that hallucination-related harms have been severely misunderstood. Furthermore, we study the role of consistency in hallucination detection and mitigation. We find that: (a) detection techniques detect consistency, not correctness, and (b) mitigation techniques like RAG, while beneficial, can introduce additional inconsistencies. By integrating prompt multiplicity into hallucination evaluation, we provide an improved framework of potential harms and uncover critical limitations in current detection and mitigation strategies.
title Rethinking Hallucinations: Correctness, Consistency, and Prompt Multiplicity
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.00723