Epoch AI gives probabilistic capability rankings for Astra, Opus 5.5 and Fable 5.1

With better uncertainty estimates and a joint distribution over all models’ ECIs, we can now compare models directly.

For example, we can now say Astra has a 72% probability of being more capable than Opus 5.5, but a 99% probability of being more capable than Fable 5.1.