Benchmark Almanac

Hallucinations on production-representative prompts

GPT-5.2 3.10%
Only in system cards

Models answer prompts representative of ChatGPT production traffic. A grader with web access scores incorrect claims and responses with major errors.

In-house OpenAI evaluation. Cards report results with and without browsing.

Made by
OpenAI
Released
August 2025
Kind
Hallucination rates
Level
Everyday
Scored
Graded by a model
Answers
Open-ended
Tasks
Kept private
Strongest model tested
GPT-5.2 #50 on the capability index
Last in a system card
December 2025
Last model added
December 2025
2
Models scored in lab cards
2
System cards report it, from 1 lab

GPT-5.2 leads with 3.10%

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 GPT-5.2 3.10%
  2. 2 GPT-5 4.50%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 GPT-5.2 3.10% Dec 2025 Lab model card
2 GPT-5 4.50% Aug 2025 Lab model card

Scores over time

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

Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2026 GPT-5.2 GPT-5 0% 20% 40% 60% 80% 100% 2026 GPT-5.2

Source: Labs’ model cards

Labs report it only in system cards

We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark. Some system cards do, below.

2 system cards report it, from 1 lab

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
Dec 11, 2025 GPT-5.2 system card addendum 3.1 Average Hallucination Rate (Browsing Disabled), % incorrect claims, gpt-5.2-thinking, printed chart label (Figure 2). Responses with 1+ major incorrect claims 10.9%. Browsing enabled 0.8% and 5.8% (Figure 1) Hallucination
Aug 7, 2025 GPT-5 system card 4.5 Factuality on ChatGPT Production Traffic (Browsing Enabled), % incorrect claims (responses with 1+ major incorrect claims 4.8%) (Figure 1) Hallucination

More in Factuality

All 74 in Factuality
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  • 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%
  • 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. GPT-6 Astra 4.20%
  • Internal adversarially-designed factuality evaluations In use Models answer adversarial questions in nine categories such as history, math and code. Scored on agreement with human ideal responses. GPT-6 Luna 7.60%
  • AA-Omniscience v1.1 In use Models answer 3,000 knowledge questions in six domains without tools and may abstain. The index adds correct answers and subtracts wrong ones. Inkling 2 Small 16.1