This was also my hypothesis when I first looked at the table. However, I think this is mostly an illusion. The sample means for rare tokens will have very high standard errors and so it is the case that rare tokens will have both unusually high average KL gap and unusually negative average KL gap mostly. And indeed, the correlation between token frequency and KL gap is approximately 0.
This was also my hypothesis when I first looked at the table. However, I think this is mostly an illusion. The sample means for rare tokens will have very high standard errors and so it is the case that rare tokens will have both unusually high average KL gap and unusually negative average KL gap mostly. And indeed, the correlation between token frequency and KL gap is approximately 0.