Zero-shot Faithfulness Evaluation for Text Summarization with Foundation Language Model

Qi Jia, Siyu Ren, Yizhu Liu, Kenny Q. Zhu

Submission Type: Regular Long Paper

Submission Track: Summarization

Submission Track 2: Natural Language Generation

Keywords: Faithfulness Evaluation, Summarization Evaluation, Hallucination Detection

Abstract: Despite tremendous improvements in natural language generation, summarization models still suffer from the unfaithfulness issue. Previous work evaluates faithfulness either using models trained on the other tasks or in-domain synthetic data, or prompting a large model such as ChatGPT. This paper proposes to do zero-shot faithfulness evaluation simply with a moderately-sized foundation language model. We introduce a new metric FFLM, which is a combination of probability changes based on the intuition that prefixing a piece of text that is consistent with the output will increase the probability of predicting the output. Experiments show that FFLM performs competitively with or even outperforms ChatGPT on both inconsistency detection and faithfulness rating with 24x fewer parameters. FFLM also achieves improvements over other strong baselines.

Submission Number: 1369