Artificial Analysis Intelligence Index v5: 60% Switch to Private Test Sets, Gap Between Open and Closed Source Widens from 3 to 12 Points

Independent evaluation firm Artificial Analysis released Intelligence Index v5 on 10 27: Added Cognition's private coding evaluation FrontierCode 2.0 and Terminal-Bench-Science, replaced Humanity's Last Exam with a streamlined HLE-Diamond, removed GDPval-AA, SciCode, etc.; 60% scores come from private test sets or undisclosed answers to prevent models from gaming public benchmarks. Simultaneously launched Progress Index v1 to compare model capabilities across eras.

Independent evaluation firm Artificial Analysis released Intelligence Index v5 on 10 27: Added Cognition's private coding evaluation FrontierCode 2.0 and Terminal-Bench-Science, replaced Humanity's Last Exam with a streamlined HLE-Diamond, removed GDPval-AA, SciCode, etc.; 60% scores come from private test sets or undisclosed answers to prevent models from gaming public benchmarks. Simultaneously launched Progress Index v1 to compare model capabilities across eras.

Confidence: High (95) · Event Time 2026-10-26

Reasoning

  • Many press releases and media outlets cite this index (this issue's top pick, Gemini 4 Carbon, took the top spot with 59 points); rankings shifted significantly after the version update. At the launch of v5, Claude Opus 5.5 (max) led with 58 points, followed by GPT-6 Astra 57 and GPT-6.1 Sol 55, with Gemini 4 Argon at 50.
  • Open-weight models saw the largest drops: The highest-scoring Kimi K3.1 Pro (weights not yet released) scored 46 points, 12 points behind the leader (in v4.3, the gap was only 3 points); The Decoder noted it fell from rank 4 to rank 9. DeepSeek V4.1 Flash 1017 and GLM-5.3, which have released weights, both scored 32 points, below Claude Haiku 5.5's 36 points.
  • The four categories each account for 25%: Knowledge Work, Coding, Science, and General. The new version is more sensitive to reasoning tiers and token usage: Claude Opus 5.5 scored 35 points at the low tier and 58 points at the highest tier, with a 10-fold difference in cost per task; the median output tokens per task rose from 3.50,000 to 5.90,000.

Usage

  • The full leaderboard and methodology are available at artificialanalysis.ai; the new AA-Omniscience-Public-v1.1 public subset is on Hugging Face and can be used to self-test knowledge Q&A and hallucination rates.
  • When selecting a model, note which reasoning tier is reported; score differences between tiers for the same model can exceed 20 points.

Risks

  • A downside of private test sets is that external parties cannot verify question errors: Artificial Analysis revised ambiguous and erroneous questions in AA-Omniscience this time (as noted by The Decoder).
  • Researcher Nathan Lambert argues that the score drop for open-source models is not just about "gaming benchmarks" but also relates to the disparity in investment across various multi-domain reinforcement learning environments; category weights are set by Artificial Analysis.

Open · Artificial Analysis Publication

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