- Sam Altman, “Three Observations,” 9 February 2025. Primary source for the stated 10× annual claim and 150× GPT-4/GPT-4o token example. It is a claim by the model vendor’s CEO, not a full price-index dataset.
- Luke Emberson and David Roodman, “The plunging price of thought,” Epoch AI, 22 September 2026. Primary research: five main benchmarks; frontier method; pooled decline, subdomain ranges, time-since-first-achieved result, and caveats. Announcement thread is discovery, not a substitute for the report.
- Warmer Sun, Altman cost-of-given-level trend JSON. A named observation represented by an index and two milestones; source is Altman’s post. Confirmed live at this URL;
/future-forge/trends/…is not the mounted URL. - Emberson and Roodman, Figure 2 cost-record CSV. Primary public data underlying the chart; filtered to
bench=gpqaandlevel=0.75for the eight transcribed rows in section 03. Code and data repository.
The separate GPQA trend JSON in the learning-game workspace is a draft, not a live Warmer Sun trend. It is not offered as a public source. The paper and CSV above are the sources for the numerical claims.