Moderation is a process that is done by NESA to determine students' Assessment Marks. The Assessment Mark is the mark that reflects a student's internal performance in a particular subject and contributes 50% of their overall HSC mark for that subject, the other 50% coming from the Examination Mark (i.e. HSC exam mark). Moderation uses two elements in determining a student's Assessment Mark in a particular subject:
- The student's internal rank.
- Examination Marks achieved in that student's cohort (including their own).
Essentially, the highest Assessment Mark (i.e. that of the student ranked first) is adjusted to equal the highest Examination Mark of any student in the cohort. Similarly, the lowest Assessment Mark (i.e. that of the student ranked last) is adjusted to equal the lowest Examination Mark of any student in the cohort. Assessment Marks of students who rank in between may not necessarily equal their equivalent Examination Marks, although they will be similar. For example, suppose that you are ranked first in a subject, and that the highest HSC exam mark achieved by a student in your cohort was 95. This mark will also become your Assessment Mark.
On the other hand, an Assessment Mark is not used to determine an Examination Mark. An Examination Mark in a particular subject depends solely on the student's own performance in their HSC exam for a particular subject. It is not affected by factors such as their rank relative to their cohort or their school rank.
Scaling is a process that is done by UAC in determining students' ATARs. It is different from moderation and uses raw HSC marks (i.e. they are not aligned, as opposed to the marks that you receive in your HSC results), which are not reported to students.
Whether unfavourable performance in your internal tasks in a couple of subjects limits your ability to achieve a 99+ ATAR can depend on the effect this had on your rank, as well as the subject's unit value (for instance, unfavourable performance in a 2-unit subject can have a worse effect on your ATAR than unfavourable performance in a 1-unit subject). However, with HSC exams contributing the remaining 50%, not to mention the fact that many students were able to make a comeback under similar circumstances, you should hopefully still have a chance of achieving an ATAR that high.
I hope this helps!