Definition
Hallucination
When a language model states something false or unsupported with confidence.
Language models generate plausible text, which is not the same as true text. Hallucinations are most common when the model lacks the needed information but is asked to answer anyway.
Mitigations are architectural: ground answers in retrieved sources, require citations, instruct and test the model to say when evidence is missing, validate structured outputs, and measure faithfulness on an evaluation set.
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