The FACTS Grounding Leaderboard: Benchmarking LLMs' Ability to Ground Responses to Long-Form Input
Paper · 2025 · Alon Jacovi, Andrew Wang, Chris Alberti et al.
Summary
The paper presents FACTS Grounding, a benchmark and Kaggle-hosted leaderboard from Google DeepMind, Google Research, Google Cloud and Kaggle. It tests whether LLMs write long answers that rely strictly on a supplied document and do not add outside facts. Human annotators wrote realistic requests over web documents of up to 32k tokens. The documents cover enterprise domains such as finance, technology, retail, medicine and law. The requests include fact finding, summarization, comparison and rewriting. Prompts needing creativity, expert knowledge or mathematical reasoning were filtered out.
Scoring is automatic and runs in two stages. First, responses that ignore the user's request are disqualified. Second, the remaining responses are checked for full support by the source text. Three different LLM judges are averaged to offset each judge's tendency to favour its own outputs. Among the nine models tested, Gemini 2.0 Flash Experimental ranks first, while the OpenAI o1 models come last. The benchmark matters because it measures grounding across many task types rather than summarization alone. Its hidden split also helps protect the leaderboard from overfitting.
Key points
- The data has two splits: 860 public "Open" examples and 859 private "Blind" examples. Each example combines a system instruction, a context document of up to 32k tokens, and a user request.
- The judges are Gemini 1.5 Pro, GPT-4o and Claude 3.5 Sonnet. Each judge rated its own family's outputs about 3.23% higher on average, which is why the final score pools all three.
- Treating ineligible responses as inaccurate lowers final scores by roughly 1–5%. It also changes the ranking slightly, for example moving Gemini 1.5 Flash from first to second place.
- Final average factuality scores:
- Gemini 2.0 Flash Experimental: 83.6
- Gemini 1.5 Flash: 82.9
- Gemini 1.5 Pro: 80.0
- Claude 3.5 Sonnet: 79.4
- GPT-4o: 78.8
- OpenAI o1-mini: 62.0
- OpenAI o1-preview: 61.7
- A Condorcet-based fusion of the six split-by-judge rankings gives exactly the same order as the averaged score.
Institutions
Fields, topics and concepts
📚 Shelves 5The field of science this work belongs to (OpenAlex fields).Computer Science · 18,614 worksArtificial Intelligence · 17,965 worksArts and Humanities · 17,450 worksLanguage and Linguistics · 17,296 worksComputer Vision and Pattern Recognition · 3,486 works
🧭 Topics 1Research subjects and languages the work is about.Evaluation & benchmarks · 1,341 works
Cite
Cite as Alon Jacovi, Andrew Wang, Chris Alberti, Connie Tao, Jon Lipovetz, Kate Olszewska, Lukas Haas, Michelle Liu, Nate Keating, Adam Bloniarz, Carl Saroufim, Corey Fry, Dror Marcus, Doron Kukliansky, Gaurav Singh Tomar, James Swirhun, Jinwei Xing, Lily Wang, Madhu Gurumurthy, Michael Aaron, Moran Ambar, Rachana Fellinger, Rui Wang, Zizhao Zhang, Sasha Goldshtein and Dipanjan Das. 2025. The FACTS Grounding Leaderboard: Benchmarking LLMs' Ability to Ground Responses to Long-Form Input. arXiv:2501.03200.
@misc{jacovi2025facts,
title = {{The FACTS Grounding Leaderboard: Benchmarking LLMs' Ability to Ground Responses to Long-Form Input}},
author = {Alon Jacovi, Andrew Wang, Chris Alberti, Connie Tao, Jon Lipovetz, Kate Olszewska, Lukas Haas, Michelle Liu, Nate Keating, Adam Bloniarz, Carl Saroufim, Corey Fry, Dror Marcus, Doron Kukliansky, Gaurav Singh Tomar, James Swirhun, Jinwei Xing, Lily Wang, Madhu Gurumurthy, Michael Aaron, Moran Ambar, Rachana Fellinger, Rui Wang, Zizhao Zhang, Sasha Goldshtein and Dipanjan Das},
year = {2025},
doi = {10.48550/arxiv.2501.03200},
eprint = {2501.03200},
archivePrefix = {arXiv},
url = {https://doi.org/10.48550/arxiv.2501.03200}
}References
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