Information Extraction (IE)-based. It is not always easy to determine which part of the
4.2.1
generated text contains the knowledge that requires verification. IE-based metrics use IE models to
represent the knowledge in a simpler relational tuple format (e.g., subject, relation, object), then
verify against relation tuples extracted from the source/reference. Here, the IE model is identifying
and extracting the “facts" that require verification. In this way, words containing no verifiable
information (e.g., stopwords, conjunctions, etc) are not included in the verification step.
SurveyofHallucinationinNatural Language Generation