Glanceable code history: visualizing student code for better instructor feedback

Immediate, individualized feedback on their code helps students learning to program. However, even in short, focused exercises in active learning, teachers do not have much time to write feedback. In addition, only looking at a student's final code hides a lot of the students' learning and discovering process. We created a glanceable code history visualization that enables teachers to view a student's entire coding history quickly and efficiently. A preliminary user study shows that this visualization captures previously unseen information that allows teachers to give students better grades and give students longer feedback and better feedback that focuses not just on their final code, but all their code in between.