Understanding How HSC Scaling Works – Part 1

By December 7, 2018 FAQ No Comments
Group Of Diverse International Students Celebrating Graduation
A note before you read: Although we have used HSC and ATAR terminology (which is for NSW and ACT) in this post, the same system applies for all other states.


HSC scaling and ATAR scores are a highly confusing and misunderstood topic that only adds an extra spike of madness in the mind for the thousands of HSC participants each year.

I remember in 2013 when I completed my own HSC I had an entirely incorrect understanding of how subject scaling worked, and despite having (incorrectly) explained scaling to at least 20 of my friends, not one of them knew to correct me. Also, post HSC, many of my friends were confused as to why they had received significantly higher or lower ATARs than they had been expecting. It wasn’t that they didn’t know that the ATAR is a rank, it was more just that they hadn’t grasped the reality of what this meant in relation to the marks they were receiving.

Understanding how scaling works and how your marks will relate to your ATAR doesn’t just mean you might avoid a nasty surprise, it gives you a serious competitive advantage over your cohort.

Students Holding Question Marks

So why is scaling necessary?

Scaling occurs to normalise subjects that have more or less competitive students within them year to year. As an ATAR is determined by your ranking, it is harder to rank higher among subjects where there are more students and competition, and easier to rank higher among less students where there is less competition. If that is confusing think of it this way; a high ATAR is like a bar of chocolate. If you put that chocolate in a room with three people competing for it, there are only two other possible people who could beat you to it. Whereas if there are 20,000 people competing for the chocolate bar that means you have to be better than 19,999 other people to win the same bar of chocolate. In other words, the more students in a subject and the more competitive they are, the harder it is to rank highly among them. This would unfairly disadvantage students in that subject. To counteract this the board of studies scales up their marks to account for the added difficulty.

To make subjects comparable and rankings fair, the Board of Studies conducts thorough re-adjustment so that a student’s final ATAR is truly reflective of their performance within the state, even across vastly different subjects to those that their fellow students have completed. Remember, an ATAR is a rank not a score, this means that your HSC examination marks and your school assessment marks will not necessarily be equal to your ATAR.

For example, if both your adjusted examination and assessment marks for all subjects are 75, this may only equal an ATAR of 70 if 30% of the state got 76 or higher. Conversely, if you received marks of 30 across your subjects and the rest of the state all got 29 or below you would receive an ATAR of 99.95. This is a confusing system to understand as we automatically expect our ATAR to be similar to the marks upon which it is based. A general rule of thumb is that an average final mark of 80 across all your subjects will equal a similar ATAR, while receiving subject marks below 80 will result in relatively lower scores and vice versa.

A few things contribute to your ATAR, the two most fundamental being your internal school assessment rank, and your external examination mark. These are used to determine your final HSC score, each subjects study score, your aggregate study score, and finally your ATAR.

“The scaling process means that contrary to popular belief the best method for obtaining a high ATAR isn’t to choose high scaling subjects, but rather to choose subjects where you are confident of performing highly in comparison to other students in your school and state. Inevitably this involves choosing subjects that you find interesting, engaging and relevant.”

If scaling has left you in the dumps and now you’re unsure about what step to take, simply contact us! We can explain the scaling system to you even more and then weigh up your options so you can still get into uni! Simply email us on enquiries@pathways2uni.com.au or call 1300 eApply (327 759).

To find out more about the scaling system, and how examination marks and assessments ranks determine your ATAR, keep an eye out for Part 2 of this post coming very soon!

Alternatively you can visit a few other sites with information, including the Board of Studies and UAC sites.

Written by Alexander Worton 

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