Step 23: assistant

thinking

text

The verdict hasn't changed: the claim is still inconclusive, at even odds (credence 0.5) that AI-assisted R&D caused most of Anthropic's capability acceleration since October 2025. What has changed is the basis. The earlier pass worked from a summary of METR's 5 November 2026 report, and this pass read the report itself, through its methodology appendix.

**What the report says:**
- **There was an acceleration.** Anthropic's benchmark progress has run at about 1.9 times its earlier rate since October 2025 (95% interval 1.5 to 2.8). One alternative modelling choice puts it as low as 1.1 times. METR is confident faster scaling of training compute did not cause it.
- **AI's current share is high.** METR guesses a majority, perhaps about 80%, of the acceleration as of October 2026 is due to AI assistance.
- **The share over the whole period is lower, by an amount kept private.** METR says non-AI factors likely played a large role in late 2025, and expects the cumulative share since October 2025 to fall below the October 2026 figure. Anthropic's growth before late 2025 was also below the industry frontier, so some of the measured speed-up may be catch-up. Anthropic redacted METR's detailed cumulative estimates and most of the evidence behind them.

The claim covers the whole period. If AI's share rose from a modest level in late 2025 to about 80% by late 2026, the cumulative share comes out near half. So the evidence clearly favours AI as the main cause of the late-2026 acceleration, but not over the whole period.

**Changes made this pass:**
- **Confidence and yield:** confidence that "inconclusive" is the right reading rose from 0.6 to 0.65. The expected gain from another pass fell from 0.6 to 0.3, because the evidence that would settle it is redacted.
- **Structure:** the claim had none. It now links three existing nodes: the 1.9x-acceleration claim (taken as given), the October 2026 attribution-share figure (supports), and the late-2025 non-AI factors claim (counts against). It also has one argument for and one against; each is rated as giving only slight support even if its premises hold.
- **Source record:** the claim's one recorded passage from the METR report was about autonomous AI contributions, not attribution. I replaced it with the report's attribution sentence and recorded a reading noting the evidence is not public. I also filed the one leftover passage from the report as a mention under the "for" argument.
- **Importance and contestation:** left at 0.55 and 0.6.

I logged the decision and answered the mandate's message. I didn't notify any other nodes, since the verdict didn't change. The pass spent about $0.54 of its $1.00 budget. Publication of METR's redacted cumulative estimate, or an independent breakdown of the speed-up, would settle the question.