Benchmark Almanac

HealthBench Professional

Claude Sonnet 5.5 69.2% leads since September 2026
GPT-5.4 59% leads since April 2026
Claude Sonnet 5.5 69.2% leads since September 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.

Made by
OpenAI
Released
April 2026
Kind
Medicine
Level
Expert
Scored
Graded by a model
Answers
Open-ended
Tasks
All public
Strongest model tested
Claude Fable 5.2 #1 on the capability index
Last in a launch post
October 2026
Last model added
November 2026
Scores refreshed
November 12th, 2026

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)
26
Models scored in lab cards
16
Launch posts list it, from 6 labs
32
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.

GPT-5.4 leads with 59% across all independent runs

Best score per model across the official leaderboard, Epoch AI’s own runs and any board Epoch AI copied. Each bar and row names its source.

Claude Sonnet 5.5 leads with 69.2%, claims included

Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.

  1. 1 Claude Sonnet 5.5 69.2%
  2. 2 Gemini 4 Argon 68.8%
  3. 3 Claude Fable 5.2 67.7%
  4. 4 Claude Fable 5 66%
  5. 5 Claude Opus 5.5 65.6%
  6. 6 Ling-3.1-flash 65.3%
  7. 7 Claude Haiku 5.5 64.8%
  8. 8 GPT-6 Astra 64.7%
  9. 9 GPT-6.1 Sol 64.2%
  10. 10 GPT-6.1 Terra 62.7%
  11. 11 Muse Wonder Full 62.3%
  12. 12 Claude Fable 5.1 62.1%
  13. 13 GPT-6 Luna 60.8%
  14. 14 GPT-6 Sol 60.8%
  15. 15 GPT-5.6 Sol 60.5%
  16. 16 Muse Wonder 60.5%
  17. 17 Claude Opus 5 59.8%
  18. 18 Muse Spark 1.1 59.3%
  19. 19 Claude Sonnet 5 57.8%
  20. 20 GPT-5.6 Terra 57.7%
  21. 21 Grok 4.7 56.7%
  22. 22 Claude Opus 4.8 55.8%
  23. 23 GPT-5.6 Luna 55.7%
  24. 24 GPT-5.5 51.8%
  25. 25 GPT-5.5 Instant 38.4%
  26. 26 MAI-Thinking-1 35%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 Claude Sonnet 5.5 69.2% Sep 2026 Lab model card
2 Gemini 4 Argon 68.8% Oct 2026 Lab model card
3 Claude Fable 5.2 67.7% Nov 2026 Lab model card
4 Claude Fable 5 66% Jun 2026 Lab model card
5 Claude Opus 5.5 65.6% Sep 2026 Lab model card
6 Ling-3.1-flash 65.3% Oct 2026 Lab model card
7 Claude Haiku 5.5 64.8% Oct 2026 Lab model card
8 GPT-6 Astra 64.7% Sep 2026 Lab model card
9 GPT-6.1 Sol 64.2% Sep 2026 Lab model card
10 GPT-6.1 Terra 62.7% Oct 2026 Lab model card
11 Muse Wonder Full 62.3% Oct 2026 Lab model card
12 Claude Fable 5.1 62.1% Sep 2026 Lab model card
13 GPT-6 Luna 60.8% Sep 2026 Lab model card
14 GPT-6 Sol 60.8% Sep 2026 Lab model card
15 GPT-5.6 Sol 60.5% Jul 2026 Lab model card
16 Muse Wonder 60.5% Oct 2026 Lab model card
17 Claude Opus 5 59.8% Jul 2026 Lab model card
18 Muse Spark 1.1 59.3% Jul 2026 Lab model card
19 Claude Sonnet 5 57.8% Jun 2026 Lab model card
20 GPT-5.6 Terra 57.7% Jul 2026 Lab model card
21 Grok 4.7 56.7% Sep 2026 Lab model card
22 Claude Opus 4.8 55.8% May 2026 Lab model card
23 GPT-5.6 Luna 55.7% Jul 2026 Lab model card
24 GPT-5.5 51.8% Apr 2026 Lab model card
25 GPT-5.5 Instant 38.4% May 2026 Lab model card
26 MAI-Thinking-1 35% Jun 2026 Lab model card
#ModelScoreSettingDateSource
1 GPT-5.4 59% ChatGPT for Clinicians Mar 2026 Official leaderboard
2 Claude Opus 4.7 47% Apr 2026 Official leaderboard
3 GPT-5 46.2% Aug 2025 Official leaderboard
4 GPT-5.2 45.9% Dec 2025 Official leaderboard
5 Gemini 3.1 Pro 43.8% Feb 2026 Official leaderboard
6 Grok 4.20 36.1% Feb 2026 Official leaderboard
#ModelScoreSettingDateSource
1 Claude Sonnet 5.5 69.2% Sep 2026 Lab model card
2 Gemini 4 Argon 68.8% Oct 2026 Lab model card
3 Claude Fable 5.2 67.7% Nov 2026 Lab model card
4 Claude Fable 5 66% Jun 2026 Lab model card
5 Claude Opus 5.5 65.6% Sep 2026 Lab model card
6 Ling-3.1-flash 65.3% Oct 2026 Lab model card
7 Claude Haiku 5.5 64.8% Oct 2026 Lab model card
8 GPT-6 Astra 64.7% Sep 2026 Lab model card
9 GPT-6.1 Sol 64.2% Sep 2026 Lab model card
10 GPT-6.1 Terra 62.7% Oct 2026 Lab model card
11 Muse Wonder Full 62.3% Oct 2026 Lab model card
12 Claude Fable 5.1 62.1% Sep 2026 Lab model card
13 GPT-6 Luna 60.8% Sep 2026 Lab model card
14 GPT-6 Sol 60.8% Sep 2026 Lab model card
15 GPT-5.6 Sol 60.5% Jul 2026 Lab model card
16 Muse Wonder 60.5% Oct 2026 Lab model card
17 Claude Opus 5 59.8% Jul 2026 Lab model card
18 Muse Spark 1.1 59.3% Jul 2026 Lab model card
19 GPT-5.4 59% ChatGPT for Clinicians Mar 2026 Official leaderboard
20 Claude Sonnet 5 57.8% Jun 2026 Lab model card
21 GPT-5.6 Terra 57.7% Jul 2026 Lab model card
22 Grok 4.7 56.7% Sep 2026 Lab model card
23 Claude Opus 4.8 55.8% May 2026 Lab model card
24 GPT-5.6 Luna 55.7% Jul 2026 Lab model card
25 GPT-5.5 51.8% Apr 2026 Lab model card
26 Claude Opus 4.7 47% Apr 2026 Official leaderboard
27 GPT-5 46.2% Aug 2025 Official leaderboard
28 GPT-5.2 45.9% Dec 2025 Official leaderboard
29 Gemini 3.1 Pro 43.8% Feb 2026 Official leaderboard
30 GPT-5.5 Instant 38.4% May 2026 Lab model card
31 Grok 4.20 36.1% Feb 2026 Official leaderboard
32 MAI-Thinking-1 35% Jun 2026 Lab model card

The benchmark's own leaderboard has 6 models. Switch the scores above to rank them together.

4 models have held number one in labs’ own numbers since its release in April 2026 Number one over time 3 models have held number one with claims included since its release in April 2026

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.

OpenAI Anthropic
Own leaderboard Not tested since Apr 2026
GPT-5.4 59%
Lab claims 4 leaders

Sources: Official HealthBench Professional leaderboard and labs’ model cards

Scores over time

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% 2026 2027 Near the ceiling (85%) Claude Sonnet 5.5 Claude Fable 5 GPT-5.4 GPT-5 0% 20% 40% 60% 80% 100% 2026 2027 Near the ceiling (85%) Claude Sonnet 5.5 GPT-5.4

Sources: Official HealthBench Professional leaderboard and labs’ model cards

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

32 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
Nov 9, 2026 Claude Fable 5.2 system card 67.7 HealthBench Professional, length-adjusted score at max effort, following Fable 5.1 metric choice. Raw score 71.1%. Artificial Analysis run with GPT-5.4 low-effort grader and fallbacks. Not comparable with prior Anthropic-graded runs (Section 8.16.2) Health
Oct 29, 2026 GPT-6 Luna system card addendum 47.4 HealthBench Professional, length-adjusted (Table 5) Health
Oct 26, 2026 GPT-6.1 Terra system card addendum 62.7 HealthBench Professional, length-adjusted (unadjusted 64.2) (HealthBench table, 5.1) Health
Oct 13, 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
Oct 12, 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
Oct 12, 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
Oct 7, 2026 GPT-6 Sol system card addendum 55.2 HealthBench Professional, length-adjusted (Table 5) Health
Oct 7, 2026 GPT-6 Luna system card addendum 48.2 HealthBench Professional, length-adjusted (Table 5) Health
Oct 7, 2026 Claude Haiku 5.5 system card 64.8 HealthBench Professional, length-adjusted, max effort (raw 71.0) (Table 8.1.A) Health
Sep 29, 2026 GPT-6.1 Sol system card addendum 64.2 HealthBench Professional, length-adjusted (Table 7) Health
Sep 28, 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
Sep 22, 2026 GPT-6 Sol system card 60.8 HealthBench Professional, length-adjusted (Table 29, A.4.1) Health
Sep 22, 2026 GPT-6 Luna system card 60.8 HealthBench Professional, length-adjusted (Table 29, A.4.1) Health
Sep 22, 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
Sep 21, 2026 Grok 4.7 model card 56.7 HealthBench Professional, xhigh, graded by Grok 4.6 (high), filtered tasks scored zero (5.1) Health
Sep 3, 2026 GPT-6 Astra system card 64.7 HealthBench Professional, length-adjusted, revised 2026-09-22 (Table 6) Health
Sep 1, 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
Aug 6, 2026 GPT-5.6 Sol system card addendum 54 HealthBench Professional, length-adjusted (5.1 table) Health
Aug 6, 2026 GPT-5.6 Luna system card addendum 44.1 HealthBench Professional, length-adjusted (5.1 table) Health
Jul 24, 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
Jul 9, 2026 GPT-5.6 Terra system card 57.7 HealthBench Professional, length-adjusted (5.1 table) Health
Jul 9, 2026 GPT-5.6 Sol system card 60.5 HealthBench Professional, length-adjusted (5.1 table) Health
Jul 9, 2026 GPT-5.6 Luna system card 55.7 HealthBench Professional, length-adjusted (5.1 table) Health
Jul 9, 2026 Muse Spark 1.1 system card 59.3 HealthBench Professional (Figure 44) Health
Jun 30, 2026 Claude Sonnet 5 system card 57.8 HealthBench Professional, length-adjusted, max effort, five trials (Table 8.1.A, 8.12.2) Health
Jun 25, 2026 GPT-5.6 Terra system card 57.7 HealthBench Professional, length-adjusted (5.1 table) Health
Jun 25, 2026 GPT-5.6 Sol system card 60.5 HealthBench Professional, length-adjusted (5.1 table) Health
Jun 25, 2026 GPT-5.6 Luna system card 55.7 HealthBench Professional, length-adjusted (5.1 table) Health
Jun 2, 2026 MAI-Thinking-1 technical report 35 HealthBench Prof., length-penalized, GPT-5.4 grader (Table 12, rounded) Health
May 28, 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
May 4, 2026 GPT-5.5 Instant system card 38.4 HealthBench Professional, length-adjusted, unadjusted 40.7 (Table 5) Health
Apr 23, 2026 GPT-5.5 system card 51.8 HealthBench Professional, length-adjusted (Table 7) Health

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