Beyond One-Size-Fits-All: Inversion Learning for Highly Effective NLG Evaluation Prompts

Hanhua Hong, Chenghao Xiao, Yang Wang, Yiqi Liu, Wenge Rong, and Chenghua Lin published a paper in Transactions of the Association for Computational Linguistics Volume 14, pages 689–710, proposing an inversion learning method that learns reverse mappings from model outputs back to their input instructions to automatically generate model-specific evaluation prompts for natural language generation systems. The method requires only a single evaluation sample and removes the need for manual prompt engineering, which the authors say improves both efficiency and robustness of LLM-based evaluation. The paper, DOI 10.1162/tacl.a.617, appears in the 2026 TACL volume published by MIT Press.

Abstract Evaluating natural language generation systems is challenging due to the diversity of valid outputs. While human evaluation is the gold standard, it suffers from inconsistencies, lack of standardization, and demographic biases, limiting reproducibility. LLM-based evaluators offer a scalable alternative but are highly sensitive to prompt design, where small variations can lead to significant discrepancies. In this work, we propose an inversion learning method that learns effective reverse mappings from model outputs back to their input instructions, enabling the automatic generation of highly effective, model-specific evaluation prompts. Our method requires only a single evaluation sample and eliminates the need for time-consuming manual prompt engineering, thereby improving both efficiency and robustness. Our work contributes toward a new direction for more robust and efficient LLM-based evaluation. - Anthology ID: - 2026.tacl-1.31 - Volume: - Transactions of the Association for Computational Linguistics, Volume 14 https://aclanthology.org/volumes/2026.tacl-1/ - Month: - Year: - 2026 - Address: - Cambridge, MA - Venue: - TACL https://aclanthology.org/venues/tacl/ - SIG: - Publisher: - MIT Press - Note: - Pages: - 689–710 - Language: - URL: - https://aclanthology.org/2026.tacl-1.31/ https://aclanthology.org/2026.tacl-1.31/ - DOI: - 10.1162/tacl.a.617 https://doi.org/10.1162/tacl.a.617 - Cite ACL : - Hanhua Hong, Chenghao Xiao, Yang Wang, Yiqi Liu, Wenge Rong, and Chenghua Lin. 2026. Beyond One-Size-Fits-All: Inversion Learning for Highly Effective NLG Evaluation Prompts https://aclanthology.org/2026.tacl-1.31/ . Transactions of the Association for Computational Linguistics , 14:689–710. - Cite Informal : - Beyond One-Size-Fits-All: Inversion Learning for Highly Effective NLG Evaluation Prompts https://aclanthology.org/2026.tacl-1.31/ Hong et al., TACL 2026 - PDF: - https://aclanthology.org/2026.tacl-1.31.pdf https://aclanthology.org/2026.tacl-1.31.pdf