Weibull fits to OpenAI internal data: time horizons doubling every 58-87 days

BasilHalperin · x · 2026-11-09

BasilHalperin fits a Weibull distribution (building on Gus Hamilton and Toby Ord's hazard-rate work) to OpenAI's internal research task data, finding time horizons doubling quickly at every success threshold:

Toby Ord's post explains that AI agents' hazard rates systematically decline as tasks go on (Weibull k<1), meaning success rates beyond the 50% horizon are better than a constant-hazard model predicts, and worse below it. All three fitting methods converge on rapidly doubling time horizons.

Related event: OpenAI internal data shows 15-minute 80% time horizon with method-dependent doubling speed(20 posts)→

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