Effective Feature Learning with Unsupervised Learning for Improving the Predictive Models in Massive Open Online Courses
This work addresses the problem of feature engineering for personalized intervention in MOOCs, which is incremental as it applies existing unsupervised techniques to a specific domain.
The paper tackles the challenge of designing effective handcrafted features for predictive models in MOOCs by using an unsupervised learning approach with a modified auto-encoder and LSTM network to learn compact representations from raw data, resulting in up to 17% improvement in prediction accuracy for student performance tasks.
The effectiveness of learning in massive open online courses (MOOCs) can be significantly enhanced by introducing personalized intervention schemes which rely on building predictive models of student learning behaviors such as some engagement or performance indicators. A major challenge that has to be addressed when building such models is to design handcrafted features that are effective for the prediction task at hand. In this paper, we make the first attempt to solve the feature learning problem by taking the unsupervised learning approach to learn a compact representation of the raw features with a large degree of redundancy. Specifically, in order to capture the underlying learning patterns in the content domain and the temporal nature of the clickstream data, we train a modified auto-encoder (AE) combined with the long short-term memory (LSTM) network to obtain a fixed-length embedding for each input sequence. When compared with the original features, the new features that correspond to the embedding obtained by the modified LSTM-AE are not only more parsimonious but also more discriminative for our prediction task. Using simple supervised learning models, the learned features can improve the prediction accuracy by up to 17% compared with the supervised neural networks and reduce overfitting to the dominant low-performing group of students, specifically in the task of predicting students' performance. Our approach is generic in the sense that it is not restricted to a specific supervised learning model nor a specific prediction task for MOOC learning analytics.