Similarity-Based Grading Assistance for Assignments in Programming Lecture

In programming classes, instructors often assign coding problems to students to assess their level of understanding. We propose to visualize the similarity between students’ source code to assist grading their submitted codes and keeping fairness and integrity in grading. Similarity is measured by the length of identical token sequences between the submitted codes. Visualization experiments were conducted with C source codes submitted by about 170 students in assignments in a second-year programming course. Our visualization with the network diagrams is visible, which makes it possible to easily identify groups of students who share their source code in each assignment and allows us to give the same grade to the same or very similar ones. This significantly helps to maintain fairness in grading assignments.