PromptDA: Label-guided Data Augmentation for Prompt-based Few Shot Learners

Recent advances on large pre-trained language models (PLMs) lead impressive gains on natural language understanding (NLU) tasks with task-specific fine-tuning. However, direct fine-tuning PLMs heavily relies on large amount of labeled instances, which are expensive and time-consuming to obtain. Prompt-based tuning on PLMs has proven valuable for few shot tasks. Existing works studying prompt-based tuning for few-shot NLU mainly focus on deriving proper label words with a verbalizer or generating prompt templates for eliciting semantics from PLMs. In addition, conventional data augmentation methods have also been verified useful for few-shot tasks. However, there currently are few data augmentation methods designed for the prompt-based tuning paradigm. Therefore, we study a new problem of data augmentation for prompt-based few shot learners. Since label semantics are helpful in prompt-based tuning, we propose a novel label-guided data augmentation method PromptDA which exploits the enriched label semantic information for data augmentation. Experimental results on several few shot text classification tasks show that our proposed framework achieves superior performance by effectively leveraging label semantics and data augmentation in language understanding