Themis: A Reference-free NLG Evaluation Language Model with Flexibility and Interpretability

Xinyu Hu, Li Lin, Mingqi Gao, Xunjian Yin, Xiaojun Wan


Abstract
The evaluation of natural language generation (NLG) tasks is a significant and longstanding research area. With the recent emergence of powerful large language models (LLMs), some studies have turned to LLM-based automatic evaluation methods, which demonstrate great potential to become a new evaluation paradigm following traditional string-based and model-based metrics. However, despite the improved performance of existing methods, they still possess some deficiencies, such as dependency on references and limited evaluation flexibility. Therefore, in this paper, we meticulously construct a large-scale NLG evaluation corpus **NLG-Eval** with annotations from both human and GPT-4 to alleviate the lack of relevant data in this field. Furthermore, we propose **Themis**, an LLM dedicated to NLG evaluation, which has been trained with our designed multi-perspective consistency verification and rating-oriented preference alignment methods. Themis can conduct flexible and interpretable evaluations without references, and it exhibits superior evaluation performance on various NLG tasks, simultaneously generalizing well to unseen tasks and surpassing other evaluation models, including GPT-4.
Anthology ID:
2024.emnlp-main.891
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
15924–15951
Language:
URL:
https://aclanthology.org/2024.emnlp-main.891
DOI:
Bibkey:
Cite (ACL):
Xinyu Hu, Li Lin, Mingqi Gao, Xunjian Yin, and Xiaojun Wan. 2024. Themis: A Reference-free NLG Evaluation Language Model with Flexibility and Interpretability. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 15924–15951, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
Themis: A Reference-free NLG Evaluation Language Model with Flexibility and Interpretability (Hu et al., EMNLP 2024)
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https://aclanthology.org/2024.emnlp-main.891.pdf