2019

Distributionally Robust Language Modeling

Oren, Yonatan, Sagawa, Shiori, Hashimoto, Tatsunori B. et al.

Understand

Language models are generally trained on data spanning a wide range of topics (e.g., news, reviews, fiction), but they might be applied to an a priori unknown target distribution (e.g., restaurant reviews).

  • In this paper, we first show that training on text outside the test distribution can degrade test performance when using standard maximum likelihood (MLE) training.
  • To remedy this without the knowledge of the test distribution, we propose an approach which trains a model that performs well over a wide range of potential test distributions.
  • In particular, we derive a new distributionally robust optimization (DRO) procedure which minimizes the loss of the model over the worst-case mixture of topics with sufficient overlap with the training distribution.

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