Benchmark Almanac

FACTS Grounding

Kimi K2 Jul 2025 88.5% leads since Jul 2025 Dropped

Long-form responses must be fully grounded in a provided document. Judged by LLM panels for grounding and eligibility.

Public split of 3,513 examples plus a private evaluation set.

In the authors’ words

We introduce FACTS Grounding, an online leaderboard and associated benchmark that evaluates language models' ability to generate text that is factually accurate with respect to given context in the user prompt. In our benchmark, each prompt includes a user request and a full document, with a maximum length of 32k tokens, requiring long-form responses. The long-form responses are required to be fully grounded in the provided context document while fulfilling the user request. Models are evaluated using automated judge models in two phases: (1) responses are disqualified if they do not fulfill the user request; (2) they are judged as accurate if the response is fully grounded in the provided document. The automated judge models were comprehensively evaluated against a held-out test-set to pick the best prompt template, and the final factuality score is an aggregate of multiple judge models to mitigate evaluation bias. The FACTS Grounding leaderboard will be actively maintained over time, and contains both public and private splits to allow for external participation while guarding the integrity of the leaderboard. It can be found at https://www.kaggle.com/facts-leaderboard.

Abstract of The FACTS Grounding Leaderboard: Benchmarking LLMs' Ability to Ground Responses to Long-Form Input (arXiv:2501.03200, CC0)
Made by Google DeepMind + Kaggle Released Jan 2025 Faithful to sources Public tasks plus a private test set Last in a launch post Sep 2025 , dropped after it saturated Last model added Oct 2026 Scores refreshed 2 Nov 2026
Level
University Undergraduates and entry-level professionals
Scored
Graded by a model A language model scores each response, usually against a rubric.
Answers
Open-ended Free-form text, documents, designs or media judged as a whole.
15
Models scored in lab cards
10
Launch posts list it, from 1 lab
11
System cards report it, from 2 labs

Kimi K2 leads with 88.5%

Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.

  1. 1 Kimi K2 Jul 2025 88.5%
  2. 2 Gemini 2.5 Pro Jun 2025 87.8%
  3. 3 Gemini 2.5 Flash Sep 2025 87.5%
  4. 4 Gemini 2.5 Flash-Lite Sep 2025 87.5%
  5. 5 Gemini 2.5 Flash-Lite Jun 2025 86.8%
  6. 6 Gemini 2.5 Flash Jun 2025 85.3%
  7. 7 Gemini 2.0 Flash Feb 2025 84.6%
  8. 8 Gemini 2.0 Flash Dec 2024 83.6%
  9. 9 Gemini 2.0 Flash-Lite 83.6%
  10. 10 Gemini 2.0 Pro 82.8%
  11. 11 Gemini 4 Argon 79%
  12. 12 Gemma 3 12B 75.8%
  13. 13 Gemma 3 27B 74.9%
  14. 14 Gemma 3 4B 70.1%
  15. 15 Gemma 3 1B 36.4%
#ModelScoreSettingDateSource
1 Kimi K2 Jul 2025 88.5% Jul 2025 Model card
2 Gemini 2.5 Pro Jun 2025 87.8% Jun 2025 Model card
3 Gemini 2.5 Flash Sep 2025 87.5% Sep 2025 Model card
4 Gemini 2.5 Flash-Lite Sep 2025 87.5% Sep 2025 Model card
5 Gemini 2.5 Flash-Lite Jun 2025 86.8% Jun 2025 Model card
6 Gemini 2.5 Flash Jun 2025 85.3% Jun 2025 Model card
7 Gemini 2.0 Flash Feb 2025 84.6% Feb 2025 Model card
8 Gemini 2.0 Flash Dec 2024 83.6% Dec 2024 Model card
9 Gemini 2.0 Flash-Lite 83.6% Feb 2025 Model card
10 Gemini 2.0 Pro 82.8% Feb 2025 Model card
11 Gemini 4 Argon 79% Oct 2026 Model card
12 Gemma 3 12B 75.8% Mar 2025 Model card
13 Gemma 3 27B 74.9% Mar 2025 Model card
14 Gemma 3 4B 70.1% Mar 2025 Model card
15 Gemma 3 1B 36.4% Mar 2025 Model card

The benchmark's own leaderboard has 35 entries, 34 of them models we track. We plot every source in the charts below.

3 models have held number one since its release in Jan 2025

Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard and what labs claim in their cards.

Anthropic Google DeepMind Moonshot AI
Own leaderboard Passed 85% in Feb 2025, by Gemini 2.0 Flash
Lab claims Passed 85% in Jun 2025, by Gemini 2.5 Pro
Kimi K2 88.5%

The best score passed 85% in Feb 2025

All the scores we have, one dot each, so a model tested at several settings appears more than once.

On the benchmark’s own leaderboard Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2024 2025 2026 Near the ceiling (85%) Kimi K2 Gemini 2.0 Flash Claude 3.5 Sonnet Mixtral 8x22B 0% 20% 40% 60% 80% 100% 2024 2025 2026 Near the ceiling (85%) Kimi K2 Mixtral 8x22B

Labs dropped it from launch posts once the best score passed 85%

Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.

Google DeepMind
DateLaunch postScoreAs the post writes it
25 Sep 2025 Gemini 2.5 Flash-Lite 87.5 FACTS Grounding, Thinking
25 Sep 2025 Gemini 2.5 Flash 87.5 FACTS Grounding, model card
17 Jun 2025 Gemini 2.5 Flash 85.3 FACTS Grounding
17 Jun 2025 Gemini 2.5 Flash-Lite 86.8 FACTS Grounding, Thinking
17 Jun 2025 Gemini 2.5 Pro 87.8 FACTS Grounding
12 Mar 2025 Gemma 3 27B 74.9 FACTS Grounding (IT)
5 Feb 2025 Gemini 2.0 Flash-Lite 83.6 FACTS Grounding
5 Feb 2025 Gemini 2.0 Flash 84.6 FACTS Grounding
5 Feb 2025 Gemini 2.0 Pro 82.8 FACTS Grounding
11 Dec 2024 Gemini 2.0 Flash 83.6 FACTS Grounding

11 system cards report it, from 2 labs

Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.

DateDocumentScoreAs the document writes itSection
13 Oct 2026 Gemini 4 Argon system card 79 FACTS Grounding factuality score 79.0% (Figure 5.13) Hallucination
26 Sep 2025 Gemini 2.5 Flash model card 87.5 Factuality FACTS Grounding (Table, pp.4 to 5) Hallucination
21 Jul 2025 Kimi K2 technical report 88.5 FACTS Grounding (Adjusted) (Table 3) Hallucination
7 Jul 2025 Gemini 2.5 Pro technical report 87.8 FACTS Grounding (Table 3) Capabilities
7 Jul 2025 Gemini 2.5 Flash technical report 85.3 FACTS Grounding (Table 3) Capabilities
15 Apr 2025 Gemini 2.0 Flash model card 84.6 FACTS Grounding (Table, p.3, column Gemini 2.0 Flash (GA)) Capabilities
10 Apr 2025 Gemini 2.0 Flash-Lite model card 83.6 FACTS Grounding (Table, p.3) Capabilities
25 Mar 2025 Gemma 3 4B technical report 70.1 FACTS Grounding, IT, zero-shot (Table 6) Capabilities
25 Mar 2025 Gemma 3 27B technical report 74.9 FACTS Grounding, IT, zero-shot (Table 6) Capabilities
25 Mar 2025 Gemma 3 1B technical report 36.4 FACTS Grounding, IT, zero-shot (Table 6) Capabilities
25 Mar 2025 Gemma 3 12B technical report 75.8 FACTS Grounding, IT, zero-shot (Table 6) Capabilities

Versions

We switch the top row to each new version when it comes out. Open it for one row per version. An old version stays in play while people still test it, so whoever first takes it past 85% gets credit for closing it out.

Google DeepMind Moonshot AI OpenAI
FACTS Grounding v2 8 leaders
GPT-6 Astra 80.1%
FACTS Grounding Passed 85% in Feb 2025, by Gemini 2.0 Flash
Kimi K2 88.5%
FACTS Grounding v2 4 leaders
GPT-6 Astra 80.1%

More in Factuality

All 70 in Factuality
  • SimpleVQA In use Models answer 2,025 short factual questions about images across 9 tasks and 9 topics. An LLM judge grades answers against fixed references. Qwen3.7-Plus 81.7%
  • HallusionBench In use Models answer 1,129 yes or no questions about 346 images, built in pairs to expose language hallucination and visual illusion. Scored by accuracy. Keye-VL-2.0-30B-A3B 73.5%
  • SimpleQA Verified In use 1,000 human-verified, de-duplicated short-answer factual questions measuring parametric knowledge. Gemini 3.1 Pro 77.5%
  • GaRAGe In use Models write long-form RAG answers to 2,366 questions with human-annotated grounding passages. Scoring checks whether answers use the relevant passages. Nemotron 3.5 Bolt E4B 40.7%
  • Kimi Hallu Bench In use Models answer hard prompts drawn from practical work tasks. Fact-checking agents score the share of claims that are hallucinated. Kimi K3.1 Pro 8.30%
  • RAGTruth In use A word-level annotated corpus of hallucinations in retrieval-augmented generation answers. It is used to train and evaluate hallucination detection and RAG faithfulness. Nemotron 3.5 Bolt E4B 77.9%