Optimization before Evaluation: Evaluation with Unoptimized Prompts Can be Misleading
Nicholas Sadjoli, Tim Siefken, Atin Ghosh, Yifan Mai, Daniel Dahlmeier
Abstract
Current Large Language Model (LLM) evaluation frameworks utilize the same static prompt template across all models under evaluation. This differs from the common industry practice of using prompt optimization (PO) techniques to optimize the prompt for each model to maximize application performance. In this paper, we investigate the effect of PO towards LLM evaluations. Our results on public academic and internal industry benchmarks show that PO greatly affects the final ranking of models. This highlights the importance of practitioners performing PO per model when conducting evaluations to choose the best model for a given task.- Anthology ID:
- 2025.acl-industry.44
- Volume:
- Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 6: Industry Track)
- Month:
- July
- Year:
- 2025
- Address:
- Vienna, Austria
- Editors:
- Georg Rehm, Yunyao Li
- Venue:
- ACL
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 619–638
- Language:
- URL:
- https://preview.aclanthology.org/corrections-2025-08/2025.acl-industry.44/
- DOI:
- 10.18653/v1/2025.acl-industry.44
- Cite (ACL):
- Nicholas Sadjoli, Tim Siefken, Atin Ghosh, Yifan Mai, and Daniel Dahlmeier. 2025. Optimization before Evaluation: Evaluation with Unoptimized Prompts Can be Misleading. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 6: Industry Track), pages 619–638, Vienna, Austria. Association for Computational Linguistics.
- Cite (Informal):
- Optimization before Evaluation: Evaluation with Unoptimized Prompts Can be Misleading (Sadjoli et al., ACL 2025)
- PDF:
- https://preview.aclanthology.org/corrections-2025-08/2025.acl-industry.44.pdf