Automated Answer Validation using Text Similarity
Balaji Ganesan, Arjun Ravikumar, Lakshay Piplani, Rini Bhaumik, Dhivya Padmanaban, Shwetha Narasimhamurthy, Chetan Adhikary, Subhash Deshapogu
TL;DR
The paper tackles automated answer validation in science QA by learning a text-similarity metric between student responses and correct answers derived from supporting text. It uses a Siamese neural network with a distance function $D(x,y)$ and losses such as $L = \max(d(a,p) - d(a,n) + \text{margin}, 0)$ to pull similar pairs together and separate dissimilar ones, and compares against SBERT-based cosine similarity and LLM-based baselines. On the SciQ dataset, the Siamese approach achieves $84.50\%$ accuracy, outperforming SBERT at $74.90\%$, with ablation analyses underscoring the value of leveraging full support text for comparison. The work also demonstrates a Streamlit-based deployment and discusses extensions to retrieval-augmented generation and LLM-driven validation for scalable educational assessment.
Abstract
Automated answer validation can help improve learning outcomes by providing appropriate feedback to learners, and by making question answering systems and online learning solutions more widely available. There have been some works in science question answering which show that information retrieval methods outperform neural methods, especially in the multiple choice version of this problem. We implement Siamese neural network models and produce a generalised solution to this problem. We compare our supervised model with other text similarity based solutions.
