Very fascinating. I'm excited to see where they go with these data. The final paragraph is where the money is. In particular, I think it'd be interesting to

Very fascinating. I'm excited to see where they go with these data. The final paragraph is where the money is. In particular, I think it'd be interesting to track students over time. Do some clusters have more difficulty picking up later concepts? Is their submission, while correct, showing some systematic error in their mental model of the language or topic? It'd be very cool to give qualitative feedback in addition to the quantitative unit tests based on these clusters. E.g., "Your code, while correct, is demonstrating characteristics that may be less maintainable than other submissions. In addition, we recommend a review of [some topic]; using those concepts would simplify your code."