InstaJudge: Aligning Judgment Bias of LLM-as-Judge with Humans in Industry Applications

Myeongjun Erik Jang, Fran Silavong


Abstract
Automated evaluation using LLM-as-Judge offers significant practical benefits for industrial applications. However, the commonly recognized misalignment of judgment biases between humans and LLM-as-Judge hinders its usage in real-world businesses. Although preference-finetuning could be a potential solution, it is often impractical for industrial use-cases due to the scarcity of business-specific data and the infeasibility of applying it to closed models. In this paper, we propose InstaJudge, an LLM-as-Judge library that improves alignments of judgment biases through automatic prompt optimization (APO). Our library not only integrates recent APO methods within a unified framework but also introduces a novel APO approach called distribution-preserving few-shot sampling (DPFS). Experimental results verify demonstrate DPFS significantly outperforms existing LLM-as-Judge libraries, like DeepEval, and APO methods by a large margin, while being more cost efficient.
Anthology ID:
2025.emnlp-industry.82
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
November
Year:
2025
Address:
Suzhou (China)
Editors:
Saloni Potdar, Lina Rojas-Barahona, Sebastien Montella
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1158–1172
Language:
URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-industry.82/
DOI:
Bibkey:
Cite (ACL):
Myeongjun Erik Jang and Fran Silavong. 2025. InstaJudge: Aligning Judgment Bias of LLM-as-Judge with Humans in Industry Applications. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 1158–1172, Suzhou (China). Association for Computational Linguistics.
Cite (Informal):
InstaJudge: Aligning Judgment Bias of LLM-as-Judge with Humans in Industry Applications (Jang & Silavong, EMNLP 2025)
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https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-industry.82.pdf