With respect to scaling, UAC uses students' raw HSC marks. A raw HSC mark consists of two elements:
- A moderated assessment mark - As you may already be aware, the moderation process is performed by NESA and involves the use of students' ranks across their subjects in addition to the Examination Marks achieved by the students that constitute a cohort.
- A raw HSC exam mark - This is the actual mark that a student achieves in an HSC exam with no alignment. Students are not made aware of this mark, although they can request their raw Examination Marks from NESA.
Each element contributes 50% of the raw HSC mark. Once determined, UAC turns those raw HSC marks into scaled HSC marks which subsequently go into the determination of students' ATAR's. Because each element contributes 50% (i.e. UAC uses raw HSC marks that are already finalised by NESA) and given that the moderation process precedes scaling, superior performance in the HSC exam of a particular will only help maximise the raw HSC mark in that subject.
I hope this helps!