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v2026.1714 entries · CC-BY 4.0
Dictionary termTrack AStablev2026.2

Hallucination

An output from a generative AI system that is presented confidently and fluently but is factually incorrect, fabricated, or unsupported by the input data or any verifiable source — including invented citations, non-existent authors, false statistics, and incorrect quotations.

ByCASRAI Editorial Board
· Last updated 21 May 2026

Examples

Worked examples

  • Is an instance

    An LLM citing a paper with a real-looking DOI that resolves to nothing

  • Is an instance

    A chatbot attributing a plausible but invented quote to a named scholar

Counter-examples

Looks similar, but isn't

  • Not an instance

    An LLM giving a wrong answer because the user's prompt was ambiguous (this is misunderstanding, not hallucination in the technical sense)

Editorial commentary

Hallucinations are a structural property of probabilistic language models, not a bug to be patched. The disclosure-relevant implication is that any AI-generated factual content (citations, numbers, attributions) used in a scholarly work must be independently verified by the human author, who remains responsible for accuracy.

References

  • Ji et al. 2023 ‘Survey of Hallucination in NLG’ ACM Computing Surveys
  • Bender et al. 2021 ‘Stochastic Parrots’ FAccT

Also known as

Confabulation · AI fabrication

Machine-readable encodings

Use in your systems

JATS XML <role> element
xml
<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="Hallucination"
      vocab-term-identifier="https://casrai.org/dictionary/term/hallucination" />
Schema.org DefinedTerm (JSON-LD)
json
{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "name": "Hallucination",
  "identifier": "https://casrai.org/dictionary/term/hallucination",
  "description": "An output from a generative AI system that is presented confidently and fluently but is factually incorrect, fabricated, or unsupported by the input data or any verifiable source — including invented citations, non-existent authors, false statistics, and incorrect quotations.",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/generative-ai-use-and-disclosure/",
  "url": "https://casrai.org/dictionary/term/hallucination",
  "sameAs": [
    "Confabulation",
    "AI fabrication"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/"
}

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