A team is comparing evaluation metrics for an open-ended question-answering system. They find that BLEU scores are low for many correct answers, but BERTScore consistently rates them highly. Which property of BERTScore explains this discrepancy?
Show answerHide answer
BERTScore computes similarity using contextual embeddings from a pre-trained model like BERT, allowing it to recognize semantic equivalence even when surface-level tokens differ. This is why semantically correct answers score well on BERTScore but poorly on BLEU, which requires exact n-gram overlap. Option A is not the primary mechanism. Option B describes a feature of some metrics but not what distinguishes BERTScore. Option D is incorrect as BERTScore considers all tokens through its embedding-based matching.