Progression Highlighting for Programming Courses

Many CS instructors desire to see more than a student's final submission on a programming assignment, wanting visibility into how the student developed their code. Recently, program auto- graders have grown in usage. A popular cloud-based auto-grader, used in over a thousand university courses, provides a log with an entry whenever a student compiles/runs or submits their code. Beyond time/date and score, each entry links to a source code snapshot. Using that log file as input, we introduce "code progression highlighting" as a mechanism for instructors to gain visibility into students' code development. The highlighter starts with a statistical summary for each student in roster form, sortable by any statistic such as time spent, number of attempts, code size, a struggle metric, and more. For any student, an instructor can expand to view all code entries, highlighted to show changes from the previous entry (the "progression"), with statistics per entry like time spent, characters changed, current score, etc. The progression highlighter helps instructors to assist students in office hours, to detect some cheating not detectable by similarity checkers, or to see where students are struggling. Our progression highlighter is free on the web for instructors to use, simply by uploading the log file from the popular auto-grader, or from any system whose log file is converted to that format, and thus can serve the community of CS instructors to gain insights on their students' code development processes.