What Happened
A recent analysis claims that AI model progress has sharply re-accelerated. Its evidence is the chart below, "showing" Epoch’s Capabilities Index rising from 8.3 points per year before 2024 to 15.5 points per year afterward.
Here is the chart:
Epoch’s complete dataset is much less dramatic and exciting.
Here is the full chart:
So, what gives?
Well, I did the maths. And here is the answer: Using all ECI observations, and controlling for developer and model family, there is no statistically significant breakpoint. A piecewise model—which splits the series into intervals and applies a sub-function to each segment—does not improve on a purely linear trend: p = 0.615, The estimated change in slope has a confidence interval of -8.4 to +23.4 points per year.
In short, the maths shows there is no model acceleration, contrary to claims, and as expected. The result comes from selecting frontier observations only, choosing a breakpoint, ignoring variance collapse, and fitting separate lines on either side.
My earlier work on the full composite shows the stronger underlying pattern: rolling relative model gains have fallen from their 2024 peak, while model dispersion has narrowed sharply.
What It Means
- There is no evidence that model progress recently re-accelerated.
- The data are consistent with a continuing linear trend.