The ATAR is meant to be a rank, a measure of a student’s academic achievement in relation to the rest of Australia’s students that year, but it’s more commonly known as a numerical shit show fraught with confusion and statistical wizardry.

Its intent is admirable, however, and the confusion stems from the nature of the problem it attempts to solve – how can we compare students that study all different kinds of combinations of subjects in different schools that employ different tasks and standards for assessment? The answer is a process of aligning, moderating, and scaling a bunch of different marks, The end result of this process is your final ATAR.

It’s important to note that these processes are reviewed yearly to ensure accuracy and validity using sound maths, some of which is beyond my lil maths dropout brain. What’s annoying, though, is that a lot of these insights aren’t always made available to students, and certainly not in a way that’s easy to understand. The following is a breakdown of the steps involved in calculating your ATAR.

Calculating a HSC mark

The first step in determining your ATAR is calculating a HSC mark, which is the average of your HSC examination mark and your moderated school assessment mark. Your HSC exam mark is simply the mark you achieve in the HSC exam (aligned so it’s out of 100), while the moderated school assessment mark (also out of 100) is a little trickier to determine.

Moderated school assessment marks are calculated using the final assessment marks provided by your school. Since each school uses different assessment tasks and may assess to different standards, these scores must be adjusted to ensure fairness across the board. As such, the raw school assessment marks of a particular school cohort are adjusted to match their performance in the actual HSC exams.

 Scaling HSC marks

Once your final HSC marks are determined, these must be scaled to ensure courses of varying difficulties are easily compared. For example, it’s understandable that a score of 90 in English Advanced shouldn’t be equal to a score of 90 in English Extension 2, so these scores must be scaled to reflect that.

Contrary to what most people think, the way subjects scale doesn’t actually directly link to their level of difficulty. Instead, scaling depends on how well the students of a particular subject do in their other subjects. Because the students enrolled in a harder extension subject tend to be high achievers in other subjects anyway, their performance means that that harder extension subject will be scaled favourably.

It may seem like a pretty shit go for those of us who love subjects that don’t scale particularly well, but it’s important to remember that most subjects get scaled fairly evenly, with exceptions mainly given to subjects that require extra work. Not to mention, your scaled score is still going to be shit in Extension 2 Maths if you end up bombing it, so picking highly scaled subjects isn’t just a magical fix to increase your ATAR. 

Getting an ATAR

This part is actually pretty simple compared to the rest of it. Once you are given scaled marks for each unit, the marks for the best ten units are added up to get an aggregate mark out of 500. This aggregate is then compared against the entire cohort and a percentile is given corresponding to your ranking, and this percentile is converted to an ATAR.

What’s it all mean to me?

The biggest takeaway from all of this is that the calculations used to scale subjects and determine your ATAR are fuckin’ confusing – but for a reason. They’re designed to promote fairness across a range of subject choices, not discourage it.

It’s a process that designed to respond to current information on student and subject performance to ensure your final ATAR is a fair measure of your academic performance, not just the nature of your subject choices. Because of this, it’s pointless to try and game the system by simply picking highly scaled subjects. There are high ATAR achievers within all subject groups, and your final mark will still largely reflect your actual aptitude in each subject.

In order to make the most of your HSC – which involves, but isn’t just about maximising your ATAR – we recommend picking subjects that you enjoy and would be important in later life. You’ll simply do better in subjects you like and will have a hell of a better time throughout the year because of it.