ATAR scaling is the process by which raw subject scores are adjusted before they contribute to a student’s final rank. The adjustment reflects the ability profile of the cohort sitting each subject in a given year. Subjects taken predominantly by high-achieving students tend to scale upward. Subjects with a more mixed cohort tend to scale down. The practical consequence is that two students with identical raw marks can end up with noticeably different ATARs depending on which subjects they sat.