Large text corpora are the backbone of language models.
However, we have a limited understanding of the content of these corpora, including general statistics, quality, social factors, and inclusion of evaluation data (contamination) .
In this work, we proposeWhat’s In My Big Data?(wimbd) , a platform and a set of sixteen analyses that allow us to reveal and compare the contents of large text corpora.wimbdbuilds on two basic capabilities—count and search—at scale, which allows us to analyze more than 35 terabytes on a standard compute node.
We applywimbdto ten different corpora used to train popular language models, includingC4,The Pile, andRedPajama.
Our analysis uncovers several surprising and previously undocumented findings about these corpora, including the high prevalence of duplicate, synthetic, and low-quality content, personally identifiable information, toxic language, and benchmark contamination.
For instance, we find that about 50% of the documents inRedPajamaandLAION-2B-enare duplicates. In addition, several datasets used for benchmarking models trained on such corpora are contaminated with respect to important benchmarks, including the Winograd Schema Challenge and parts of GLUE and SuperGLUE.
We open-sourcewimbd’s code and artifacts to provide a standard set of evaluations for new text-based corpora and to encourage more analyses and transparency around them:github.com/allenai/wimbd.