For the generative question answering (GQA) task, the exploration of hallucination is at its early
stage, so there is no standard definition or categorization of hallucination yet. However, we can see
that the GQA literature mainly focuses on “intrinsic hallucination” where the source is the world
knowledge [102]. Lastly, unlike the aforementioned tasks, the categorizations of hallucinations in
machine translation vary within the task. Most relevant literature agrees that translated text is
considered a hallucination when the source text is completely disconnected from the translated
target [95, 132, 153]. For further details, please refer to Section 11.
SurveyofHallucinationinNatural Language Generation