METR Time Horizons and External Capability Evaluation

METR (ex-ARC Evals) is an independent 501(c)(3) since December 2023. Their Time Horizon 1.1 benchmark (January 2026) fits a logistic curve to task-success probability vs log(expert human completion time); the intersection at 50% probability defines the model's time horizon. The 2025–2026 engagement set covers GPT-5.1, GPT-5.1-Codex-Max, and prototype monitoring evaluations (can a monitor catch side tasks; can the agent evade). Benchmark suites: HCAST (180+ ML, cyber, SWE, reasoning tasks; 1 minute to 8+ hours), RE-Bench (71 ML research-engineering tasks with expert baseline), SWAA. The honest note: METR measurements are idealized — no human, no real consequences — and the team has documented the eval-vs-deployment behavior gap (Lesson 1). A time horizon is an upper bound, not a deployment prediction.