Real-World Summarization: When Evaluation Reaches Its Limits

Patrícia Schmidtová, Ondrej Dusek, Saad Mahamood


Abstract
We examine evaluation of faithfulness to input data in the context of hotel highlights—brief LLM-generated summaries that capture unique features of accommodations. Through human evaluation campaigns involving categorical error assessment and span-level annotation, we compare traditional metrics, trainable methods, and LLM-as-a-judge approaches. Our findings reveal that simpler metrics like word overlap correlate surprisingly well with human judgments (r=0.63), often outperforming more complex methods when applied to out-of-domain data. We further demonstrate that while LLMs can generate high-quality highlights, they prove unreliable for evaluation as they tend to severely under- or over-annotate. Our analysis of real-world business impacts shows incorrect and non-checkable information pose the greatest risks. We also highlight challenges in crowdsourced evaluations.
Anthology ID:
2025.findings-emnlp.1363
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
25014–25026
Language:
URL:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.1363/
DOI:
10.18653/v1/2025.findings-emnlp.1363
Bibkey:
Cite (ACL):
Patrícia Schmidtová, Ondrej Dusek, and Saad Mahamood. 2025. Real-World Summarization: When Evaluation Reaches Its Limits. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 25014–25026, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Real-World Summarization: When Evaluation Reaches Its Limits (Schmidtová et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.1363.pdf
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