  Test-time augmentation -- the aggregation of predictions across transformed
examples of test inputs -- is an established technique to improve the
performance of image classification models. Importantly, TTA can be used to
improve model performance post-hoc, without additional training. Although
test-time augmentation (TTA) can be applied to any data modality, it has seen
limited adoption in NLP due in part to the difficulty of identifying
label-preserving transformations. In this paper, we present augmentation
policies that yield significant accuracy improvements with language models. A
key finding is that augmentation policy design -- for instance, the number of
samples generated from a single, non-deterministic augmentation -- has a
considerable impact on the benefit of TTA. Experiments across a binary
classification task and dataset show that test-time augmentation can deliver
consistent improvements over current state-of-the-art approaches.
