Chris(@ChrisGPT):How much better is each internal model getting at Anthropic? Model 2: - 174.1 Model 3: - 177.0 (+2.9 points) Model 4: - 178.6 (+1.6 points) That’s a 4.5-point increase from Model 2 to Model 4. Model 2 and 3 are estimates read from METR’s chart. Keep in mind this is AECI, not Epoch’s ECI They use different methods, so we can’t tell from this whether their ECI scores would be higher. Even if you assume Model 4 is Fable 5.5, the changes are about 1.7% and 0.9% of the index scores, but AECI uses an arbitrary scale. For reference Astra scores 169 on the ECI

2026.11.06 21:16

How much better is each internal model getting at Anthropic? Model 2: - 174.1 Model 3: - 177.0 (+2.9 points) Model 4: - 178.6 (+1.6 points) That’s a 4.5-point increase from Model 2 to Model 4. Model 2 and 3 are estimates read from METR’s chart. Keep in mind this is AECI, not Epoch’s ECI They use different methods, so we can’t tell from this whether their ECI scores would be higher. Even if you assume Model 4 is Fable 5.5, the changes are about 1.7% and 0.9% of the index scores, but AECI uses an arbitrary scale. For reference Astra scores 169 on the ECI