Text Representations of Math Tutorial Videos for Clustering, Retrieval, and Learning Gain Prediction

Liamthong, Pichayut

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Text Representations of Math Tutorial Videos for Clustering, Retrieval, and Learning Gain Prediction

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With the goal of making vast collections of open educational resources (YouTube, Khan Academy, etc.) more useful to learners, we explored how automatically extractable text representations of math tutorial videos can help to categorize the videos, search through them for specific content, and predict the individual learning gains of students who watch them. In particular, (1) we devised novel text representations, based on the output of an automatic speech recognition system, that consider the frequency of different tokens (symbols, equations, etc.) as well as their proximity from each other in the transcript. Unsupervised learning experiments, conducted on 208 videos that explain 18 math problems about logarithms show that the clustering accuracy of our proposed methods reaches 85%, surpassing that of standard TF-IDF features (78% using log normalization). (2) In a video search setting, the proposed text features can significantly reduce the number of videos (up to 88% reduction on our dataset) and amount of video time (up to 82%) that users need to spend looking for desired content in large video collections. Finally, (3) in an experiment on Mechanical Turk with n = 541 participants who watched a randomly assigned tutorial video between a pretest & posttest, the text features and their multiplicative interactions with students’ prior knowledge provide a statistically significant benefit to predicting individual learning gains.

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