Entailment as Robust Self-Learner

Entailment has been recognized as an important metric for evaluating natural language understanding (NLU) models, and recent studies have found that <PRE_TAG>entailment pretraining</POST_TAG> benefits weakly supervised fine-tuning. In this work, we design a prompting strategy that formulates a number of different NLU tasks as contextual <PRE_TAG>entailment</POST_TAG>. This approach improves the zero-shot adaptation of pretrained <PRE_TAG>entailment models</POST_TAG>. Secondly, we notice that self-training entailment-based models with unlabeled data can significantly improve the adaptation performance on downstream tasks. To achieve more stable improvement, we propose the Simple Pseudo-Label Editing (SimPLE) algorithm for better pseudo-labeling quality in self-training. We also found that both pretrained entailment-based models and the self-trained models are robust against adversarial evaluation data. Experiments on binary and multi-class classification tasks show that SimPLE leads to more robust self-training results, indicating that the self-trained entailment models are more efficient and trustworthy than large language models on language understanding tasks.