Benchmark Almanac

HealthBench Professional

Claude Sonnet 5.5 69.2% leads since Sep 2026 In use

525 physician-authored tasks from real clinician chats (care consult, documentation, research) with physician-adjudicated rubrics.

Enriched about 3.5x for examples that are hard for OpenAI models. About one third adversarial.

In the authors’ words

Millions of clinicians use ChatGPT to support clinical care, but evaluations of the most common use cases in model-clinician conversations are limited. We introduce HealthBench Professional, an open benchmark for evaluating large language models on real tasks that clinicians bring to ChatGPT in the course of their work. The benchmark is organized around three common use cases central to clinical practice: care consult, writing and documentation, and medical research. Each example includes a physician-authored conversation with ChatGPT for Clinicians and is scored via rubrics written and iteratively adjudicated by three or more physicians across three phases. HealthBench Professional examples were carefully selected for quality, representativeness, and difficulty for OpenAI's current frontier models, to enable continued measurement of progress. Difficult examples for recent OpenAI models were enriched by roughly 3.5 times relative to the candidate pool of 15,079 examples. Additionally, about one-third of examples involve physicians conducting deliberate adversarial testing of models. As a strong baseline, we also collected human physician responses for all tasks (unbounded time, specialist-matched, web access). The best scoring system, GPT-5.4 in ChatGPT for Clinicians, outperforms base GPT-5.4, all other models, and human physicians. We hope HealthBench Professional provides the healthcare AI community a measure to track frontier model progress in real-world clinical tasks and build systems that clinicians can trust to improve care.

Abstract of HealthBench Professional: Evaluating Large Language Models on Real Clinician Chats (arXiv:2604.27470, CC0)
Made by OpenAI Released Apr 2026 Medicine All tasks public Last in a launch post Oct 2026 Last model added Oct 2026
Level
Expert Specialists with years of training, often over hours of work
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.
25
Models scored in lab cards
15
Launch posts list it, from 6 labs
31
System cards report it, from 6 labs

Claude Sonnet 5.5 leads with 69.2%

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 Claude Sonnet 5.5 69.2%
  2. 2 Gemini 4 Argon 68.8%
  3. 3 Claude Fable 5 66%
  4. 4 Claude Opus 5.5 65.6%
  5. 5 Ling-3.1-flash 65.3%
  6. 6 Claude Haiku 5.5 64.8%
  7. 7 GPT-6 Astra 64.7%
  8. 8 GPT-6.1 Sol 64.2%
  9. 9 GPT-6.1 Terra 62.7%
  10. 10 Muse Wonder Full 62.3%
  11. 11 Claude Fable 5.1 62.1%
  12. 12 GPT-6 Luna 60.8%
  13. 13 GPT-6 Sol 60.8%
  14. 14 GPT-5.6 Sol 60.5%
  15. 15 Muse Wonder 60.5%
  16. 16 Claude Opus 5 59.8%
  17. 17 Muse Spark 1.1 59.3%
  18. 18 Claude Sonnet 5 57.8%
  19. 19 GPT-5.6 Terra 57.7%
  20. 20 Grok 4.7 56.7%
  21. 21 Claude Opus 4.8 55.8%
  22. 22 GPT-5.6 Luna 55.7%
  23. 23 GPT-5.5 51.8%
  24. 24 GPT-5.5 Instant 38.4%
  25. 25 MAI-Thinking-1 35%
#ModelScoreSettingDateSource
1 Claude Sonnet 5.5 69.2% Sep 2026 Model card
2 Gemini 4 Argon 68.8% Oct 2026 Model card
3 Claude Fable 5 66% Jun 2026 Model card
4 Claude Opus 5.5 65.6% Sep 2026 Model card
5 Ling-3.1-flash 65.3% Oct 2026 Model card
6 Claude Haiku 5.5 64.8% Oct 2026 Model card
7 GPT-6 Astra 64.7% Sep 2026 Model card
8 GPT-6.1 Sol 64.2% Sep 2026 Model card
9 GPT-6.1 Terra 62.7% Oct 2026 Model card
10 Muse Wonder Full 62.3% Oct 2026 Model card
11 Claude Fable 5.1 62.1% Sep 2026 Model card
12 GPT-6 Luna 60.8% Sep 2026 Model card
13 GPT-6 Sol 60.8% Sep 2026 Model card
14 GPT-5.6 Sol 60.5% Jun 2026 Model card
15 Muse Wonder 60.5% Oct 2026 Model card
16 Claude Opus 5 59.8% Jul 2026 Model card
17 Muse Spark 1.1 59.3% Jul 2026 Model card
18 Claude Sonnet 5 57.8% Jun 2026 Model card
19 GPT-5.6 Terra 57.7% Jul 2026 Model card
20 Grok 4.7 56.7% Sep 2026 Model card
21 Claude Opus 4.8 55.8% May 2026 Model card
22 GPT-5.6 Luna 55.7% Jul 2026 Model card
23 GPT-5.5 51.8% Apr 2026 Model card
24 GPT-5.5 Instant 38.4% May 2026 Model card
25 MAI-Thinking-1 35% Jun 2026 Model card

4 models have held number one since its release in Apr 2026

Lab claims count from the day the card came out, independent runs from the model’s release.

OpenAI Anthropic
Lab claims 4 leaders

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 2027 Near the ceiling (85%) Claude Sonnet 5.5 Claude Fable 5 Claude Opus 4.8 0% 20% 40% 60% 80% 100% 2026 2027 Near the ceiling (85%) Claude Sonnet 5.5 Claude Opus 4.8

6 labs put it in a launch post in the last six months

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.

Microsoft
Anthropic
OpenAI
xAI
Meta
Ant Group
DateLaunch postScoreAs the post writes it
13 Oct 2026 Ling-3.1-flash 65.3 Healthbench Professional (AQ environment)
12 Oct 2026 Muse Wonder 60.5 HealthBench Pro
12 Oct 2026 Muse Wonder Full 62.3 HealthBench Pro
7 Oct 2026 Claude Haiku 5.5 64.8 HealthBench Professional (Length-adjusted)
28 Sep 2026 Claude Sonnet 5.5 69.2 HealthBench Professional
22 Sep 2026 Claude Opus 5.5 65.6 HealthBench Professional
21 Sep 2026 Grok 4.7 56.7 HealthBench Professional (Clinical reasoning)
3 Sep 2026 GPT-6 Astra 63.4 HealthBench Professional (length-adjusted)
1 Sep 2026 Claude Fable 5.1 62.1 HealthBench Professional
24 Jul 2026 Claude Opus 5 59.8 Health HealthBench Professional
9 Jul 2026 GPT-5.6 Luna 55.7 HealthBench Professional
9 Jul 2026 GPT-5.6 Terra 57.7 HealthBench Professional
30 Jun 2026 Claude Sonnet 5 57.8 HealthBench Professional
9 Jun 2026 Claude Fable 5 66 Health HealthBench Professional
2 Jun 2026 MAI-Thinking-1 35 HealthBench Prof.

31 system cards report it, from 6 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
29 Oct 2026 GPT-6 Luna system card addendum 47.4 HealthBench Professional, length-adjusted (Table 5) Health
26 Oct 2026 GPT-6.1 Terra system card addendum 62.7 HealthBench Professional, length-adjusted (unadjusted 64.2) (HealthBench table, 5.1) Health
13 Oct 2026 Gemini 4 Argon system card 68.8 HealthBench Pro, without Search grounding 68.8 (length-adjusted 56.5); with Search grounding 76.7 (length-adjusted 61.4) (Table 5.1) Health
12 Oct 2026 Muse Wonder model card 60.5 HealthBench Pro, length-normalized weighted rubric score, no tools, Muse Wonder (max) (capabilities table image, page 3) Health
12 Oct 2026 Muse Wonder Full model card 62.3 HealthBench Pro, length-normalized weighted rubric score, no tools, Muse Wonder Full (max) (capabilities table image, page 3) Health
7 Oct 2026 GPT-6 Sol system card addendum 55.2 HealthBench Professional, length-adjusted (Table 5) Health
7 Oct 2026 GPT-6 Luna system card addendum 48.2 HealthBench Professional, length-adjusted (Table 5) Health
7 Oct 2026 Claude Haiku 5.5 system card 64.8 HealthBench Professional, length-adjusted, max effort (raw 71.0) (Table 8.1.A) Health
29 Sep 2026 GPT-6.1 Sol system card addendum 64.2 HealthBench Professional, length-adjusted (Table 7) Health
28 Sep 2026 Claude Sonnet 5.5 system card 69.2 HealthBench Professional, length-adjusted at max effort (77.1% before length adjustment) (Table 8.1.A, 8.15.2) Health
22 Sep 2026 GPT-6 Sol system card 60.8 HealthBench Professional, length-adjusted (Table 29, A.4.1) Health
22 Sep 2026 GPT-6 Luna system card 60.8 HealthBench Professional, length-adjusted (Table 29, A.4.1) Health
22 Sep 2026 Claude Opus 5.5 system card 65.6 HealthBench Professional, length-adjusted at max effort (77.1% before length adjustment) (Table 8.1.A, 8.15.2) Health
21 Sep 2026 Grok 4.7 model card 56.7 HealthBench Professional, xhigh, graded by Grok 4.6 (high), filtered tasks scored zero (5.1) Health
3 Sep 2026 GPT-6 Astra system card 64.7 HealthBench Professional, length-adjusted, revised 2026-09-22 (Table 6) Health
1 Sep 2026 Claude Fable 5.1 system card 62.1 HealthBench Professional length-adjusted score (Table 8.1.A); raw score 74.2% (8.17.2) Health
6 Aug 2026 GPT-5.6 Sol system card addendum 54 HealthBench Professional, length-adjusted (5.1 table) Health
6 Aug 2026 GPT-5.6 Luna system card addendum 44.1 HealthBench Professional, length-adjusted (5.1 table) Health
24 Jul 2026 Claude Opus 5 system card 59.8 HealthBench Professional, length-adjusted at max effort (73.4% raw) (Table 8.1.A, 8.15.2) Health
9 Jul 2026 GPT-5.6 Terra system card 57.7 HealthBench Professional, length-adjusted (5.1 table) Health
9 Jul 2026 GPT-5.6 Sol system card 60.5 HealthBench Professional, length-adjusted (5.1 table) Health
9 Jul 2026 GPT-5.6 Luna system card 55.7 HealthBench Professional, length-adjusted (5.1 table) Health
9 Jul 2026 Muse Spark 1.1 system card 59.3 HealthBench Professional (Figure 44) Health
30 Jun 2026 Claude Sonnet 5 system card 57.8 HealthBench Professional, length-adjusted, max effort, five trials (Table 8.1.A, 8.12.2) Health
25 Jun 2026 GPT-5.6 Terra system card 57.7 HealthBench Professional, length-adjusted (5.1 table) Health
25 Jun 2026 GPT-5.6 Sol system card 60.5 HealthBench Professional, length-adjusted (5.1 table) Health
25 Jun 2026 GPT-5.6 Luna system card 55.7 HealthBench Professional, length-adjusted (5.1 table) Health
2 Jun 2026 MAI-Thinking-1 technical report 35 HealthBench Prof., length-penalized, GPT-5.4 grader (Table 12, rounded) Health
28 May 2026 Claude Opus 4.8 system card 55.8 HealthBench Professional, length-adjusted score, max effort, Claude Sonnet 4.6 grader, five trials (8.14.1, Figure 8.14.A) Health
4 May 2026 GPT-5.5 Instant system card 38.4 HealthBench Professional, length-adjusted, unadjusted 40.7 (Table 5) Health
23 Apr 2026 GPT-5.5 system card 51.8 HealthBench Professional, length-adjusted (Table 7) Health

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