You definitely
don't need to know about all of the intricacies of the VCE system, and how the technical side of things works. But I really had no idea about study scores, or ATARs, or scaling, or anything like that. So here are some basic things to be aware of:
ScalingSome subjects scale up; others scale down. This means that the "raw" mark you receive for that subject is adjusted, and it's the adjusted mark that counts toward your ATAR. However, this doesn't depend on how difficult a subject's content is - it would be very difficult to compare the difficulty of, say, Specialist Maths (the hardest VCE maths subject), and Studio Arts (a subject that emphasises a completely different skill set). It's not obvious here which one is "more difficult", because it will very likely change from person to person.
So how is scaling decided?
It's based on the
competitiveness of that subject - not the difficulty. Basically, VCAA looks at every single person studying a specific subject, and finds their average study score (their overall mark) for
all of their subjects. So let's say the average study score for
all Chemistry students across
all of their subjects (not just Chemistry) is 35. The average study score is usually 30, which means that, on average, the Chemistry cohort has outperformed the rest of the state, suggesting the Chem cohort was pretty strong. As a result, Chemistry scales up.
The whole point of scaling is to make VCE a fair system; it doesn't reward or punish you for taking certain subjects. So, with that in mind, it's best to not really prioritise scaling when it comes to choosing your VCE subjects.
Calculation of the ATARI wasn't really clear about this for quite a long time tbh. Basically, VCAA takes your four best Units 3/4 subjects (including at least one English subject, which is compulsory), plus 10% of your fifth and sixth best subjects if applicable. This forms your "aggregate". Everybody's aggregates are then ranked, and your ATAR is formed from that ranking.
So, just because you average 80% across the year - that definitely doesn't mean you'll get an ATAR of 80.00.
Both SACs and exams matterYour SACs are basically tests administered by your school for each subject. SACs and the exam(s) are worth different amounts depending on the subject, but, without boring you too much with the details, SACs
and exams are important for your final scores.
But you shouldn't stress too much about raw internal marksSo I've just said that your performance in SACs throughout the year (particularly in Year 12) is important, which it is. But the specific numbers don't really matter too much. Again, you can read more about it all
here if you're really interested, but the take home point is to simply try your best, and the rest will work itself out after that.