Web-crawled datasets have enabled remarkable generalization capabilities in recent image-text models such as CLIP (Contrastive Language-Image pre-training) or Flamingo, but little is known about the dataset creation processes. In this work, we introduce a testbed of six publicly available data sources - YFCC, LAION, Conceptual Captions, WIT, RedCaps, Shutterstock - to investigate how pre-training distributions induce robustness in CLIP. We find that the performance of the pre-training data varies substantially across distribution shifts, with no single data source dominating. Moreover, we systematically study the interactions between these data sources and find that combining multiple sources does not necessarily yield better models, but rather dilutes the robustness of the best individual data source. We complement our empirical findings with theoretical insights from a simple setting, where combining the training data also results in diluted robustness. In addition, our theoretical model provides a candidate explanation for the success of the CLIP-based data filtering technique recently employed in the LAION dataset. Overall our results demonstrate that simply gathering a large amount of data from the web is not the most effective way to build a pre-training dataset for robust generalization, necessitating further study into dataset design.

探究六种公开数据来源——YFCC、LAION、Conceptual Captions、WIT、RedCaps、Shutterstock——对CLIP进行预训练的分布移位是否会对性能产生影响，发现不同的预训练数据表现相差很大，并且多个数据源的组合并不一定产生更好的模型，提出从理论和实践两方面着手进行数据集设计以实现稳健一般化训练的需求。

数据集设计与CLIP鲁棒性之间的交互作用：质量胜过数量