VeriFact: Enhancing Long-Form Factuality Evaluation with Refined Fact Extraction and Reference Facts
Paper · 2025 · Xin Liu, Lechen Zhang, Sheza Munir et al.
Summary
Judging whether long LLM answers are factually correct is hard because individual claims often depend on context spread across several sentences. Existing checkers such as SAFE split a response into standalone claims and verify each one, but they tend to drop conditions, comparisons, and causal or temporal links. An annotation study of 451 SAFE-extracted facts confirmed these gaps.
The authors propose VeriFact, which keeps the decompose-decontextualize-verify pipeline but adds a stage in which several LLM judges flag incomplete or missing facts. Flagged facts are rewritten into self-contained statements and then checked against Google Search evidence.
They also release FactRBench, which provides reference fact sets so that recall can be measured alongside precision. VeriFact produces noticeably fewer incomplete and missing facts. Benchmarking twelve LLMs shows that precision and recall can diverge. This matters because a terse answer can be perfectly accurate yet leave out most of the relevant information.
Key points
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Annotation study: Responses from GPT4o-mini and Llama3.1-8B to 14 FactBench prompts were analysed. Of SAFE's extracted facts, 12.68% were incomplete, and about 1.24 relational facts were missing per response (out of roughly 24.5 extracted).
- Causes of incompleteness: omitted conditions (51%), ambiguous entities (38%), missing comparanda (6%).
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VeriFact results: It reduces incomplete facts by 19.2% compared with the strongest baseline. Its refinement stage cuts missing facts by 37%.
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FactRBench queries: These combine in-the-wild FactBench prompts with Reddit questions (e.g., r/askscience) posted after January 2024, which limits pretraining leakage.
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FactRBench references: Reference facts come from two sources:
- VeriFact-verified outputs of Claude3.5-Sonnet, GPT-4o, Gemini-1.5 and Llama3.1-405B-instruct;
- highly upvoted human answers from Reddit.
The full retrieved webpages are included to make verification reproducible.
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Benchmark of 12 LLMs (9 open-weight, 3 closed):
- Larger models within a family generally score higher on both precision and recall.
- Closed models tend to lead on recall.
- Large open models such as Mistral-123B, Llama3.1-405B and Qwen2.5-72B are competitive, especially on precision.
Institutions
Fields, topics and concepts
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Cite
Cite as Xin Liu, Lechen Zhang, Sheza Munir, Yiyang Gu and Lu Wang. 2025. VeriFact: Enhancing Long-Form Factuality Evaluation with Refined Fact Extraction and Reference Facts. Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing.
@inproceedings{liu2025verifact,
title = {{VeriFact: Enhancing Long-Form Factuality Evaluation with Refined Fact Extraction and Reference Facts}},
author = {Xin Liu, Lechen Zhang, Sheza Munir, Yiyang Gu and Lu Wang},
booktitle = {Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing},
year = {2025},
doi = {10.18653/v1/2025.emnlp-main.905},
url = {https://doi.org/10.18653/v1/2025.emnlp-main.905}
}References
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