Verify with Caution: The Pitfalls of Relying on Imperfect Factuality Metrics
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Abstract (arXiv)
Improvements in large language models have led to increasing optimism that they can serve as reliable evaluators of natural language generation outputs. In this paper, we challenge this optimism by thoroughly re-evaluating five state-of-the-art factuality metrics on a collection of 11 datasets for summarization, retrieval-augmented generation, and question answering. We find that these evaluators are inconsistent with each other and often misestimate system-level performance, both of which can lead to a variety of pitfalls. We further show that these metrics exhibit biases against highly paraphrased outputs and outputs that draw upon faraway parts of the source documents. We urge users of these factuality metrics to proceed with caution and manually validate the reliability of these metrics in their domain of interest before proceeding.
Key facts. Cited by 8 papers in the map (data through 14 Oct 2026). Builds on 19 of its 31 references that are in the map. First posted on arXiv 24 Jan 2025.
Builds on
19 of 31 references.
References · 19
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7 more
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Citing papers per year: 2025: 4; 2026: 4.
8 papers.
- 2025How to Correctly Report LLM-as-a-Judge Evaluationscited by 30
- 2025Verifying the Verifiers: Unveiling Pitfalls and Potentials in Fact Verifierscited by 13
- 2025Evaluating Evaluation Metrics -- The Mirage of Hallucination Detectioncited by 6
- 2025All Claims Are Equal, but Some Claims Are More Equal Than Others: Importance-Sensitive Factuality Evaluation of LLM Generationscited by 6
- 2026How College Students Use AI to Navigate Course Readings: Evidence from an Eight-Week Studycited by 0
- 2026Does Finetuning with Scientific Data Increase Hallucinations? A Multi-domain Factuality Evaluation of LLMscited by 0
- 2026Can We Trust the Judges? Validation of Factuality Evaluation Methods via Answer Perturbationcited by 0
- 2026RAIM: Robust Aggregation of Inexpensive Models for Hallucination Detectioncited by 0
- 2026RAIM: Robust Aggregation of Inexpensive Models for Hallucination Detection30 Sep 2026
- 2026Can We Trust the Judges? Validation of Factuality Evaluation Methods via Answer Perturbation14 Sep 2026
- 2026Does Finetuning with Scientific Data Increase Hallucinations? A Multi-domain Factuality Evaluation of LLMs19 Jun 2026
- 2026How College Students Use AI to Navigate Course Readings: Evidence from an Eight-Week Study10 Feb 2026
- 2025How to Correctly Report LLM-as-a-Judge Evaluations26 Nov 2025
- 2025All Claims Are Equal, but Some Claims Are More Equal Than Others: Importance-Sensitive Factuality Evaluation of LLM Generations8 Oct 2025
- 2025Verifying the Verifiers: Unveiling Pitfalls and Potentials in Fact Verifiers16 Jun 2025
- 2025Evaluating Evaluation Metrics -- The Mirage of Hallucination Detection25 Apr 2025
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- 2024Investigating Factuality in Long-Form Text Generation: The Roles of Self-Known and Self-Unknown
- 2024Merging Facts, Crafting Fallacies: Evaluating the Contradictory Nature of Aggregated Factual Claims in Long-Form Generations
- 2023Survey on Factuality in Large Language Models: Knowledge, Retrieval and Domain-Specificity
- 2024Provenance: A Light-weight Fact-checker for Retrieval Augmented LLM Generation Output
- 2022On Improving Summarization Factual Consistency from Natural Language Feedback
- 2024UFO: a Unified and Flexible Framework for Evaluating Factuality of Large Language Models
- 2024Long-form factuality in large language models