Few-Shot Essay Grading: Weighted Prototypical Networks for Ordinal Text Classification
Vihanga Ashinsana Wijayasekara, Kyle Martin, Nirmalie Wiratunga, Stewart Massie, Anjana Wijekoon · Frontiers in artificial intelligence and applications · 2025
Automated Essay Scoring (AES) presents a key opportunity to improve student experience while reducing the administrative burden of academic staff. However existing methods for AES are reliant on large volumes of data and fail to consider the ordinal aspect of grading. As a result, when an institution introduces a new assessment, there may be no data available to train algorithms. In this paper, we demonstrate that metric learning architectures, specifically Prototypical Networks, offer robust performance on few-shot ordinal classification essay grading tasks. We introduce three novel weighted prototype calculation strategies designed to enhance class representation in ordinal few-shot text classification. These strategies improve how class knowledge is modeled from limited examples by refining the way prototypes are computed, incorporating weighted mechanisms for better differentiation. Results across four datasets show that our methods outperform existing baselines and the current state-of-the-art in ordinal few-shot text classification. Additionally, we compare our approach with three large language models (LLMs) using a prompt-based approach to few-shot learning and find that we achieve superior or comparable performance in all evaluated tasks.