  Current trends to pre-train capable Large Language Models (LLMs) mostly focus
on scaling of model and dataset size. However, the quality of pre-training data
is an important factor for training powerful LLMs, yet it is a nebulous concept
that has not been fully characterized. Therefore, we use the recently proposed
Task2Vec diversity coefficient to ground and understand formal aspects of data
quality, to go beyond scale alone. Specifically, we measure the diversity
coefficient of publicly available pre-training datasets to demonstrate that
their formal diversity is high when compared to theoretical lower and upper
bounds. In addition, to build confidence in the diversity coefficient, we
conduct interpretability experiments and find that the coefficient aligns with
intuitive properties of diversity, e.g., it increases as the number of latent
concepts increases. We conclude the diversity coefficient is reliable, show
it's high for publicly available LLM datasets, and conjecture it can be used to
build useful diverse datasets for LLMs.
