Subject Scaling in Queensland

How subject scaling contributes to your ATAR calculation in Queensland

The following article explores subject scaling, why it is necessary and how it contributes to your ATAR calculation.

Subject scaling is the process by which the relative difficulty of subjects is taken into consideration before a student's final ATAR score is calculated.  Some subjects are harder than others (i.e. Mathematical Methods is more difficult than General Mathematics).  If every subject's raw score was used in the final ATAR calculation, very few student would choose difficult subjects as they would be at a disadvantage when it comes to getting their ATAR score.

The raw score that a student gets for each subject is moderated up or down depending on its relative difficulty compared to other subjects (Specialist Mathematics gets moderated up, General Mathematics gets moderated down etc).  The method to determine how much a subject gets moderated up or down is to look at what students get in common subjects.  A simplified version of the process goes something as follows:

Bob gets the following marks in two of his subjects:

Specialist Mathematics 100

Mathematical Methods 100

Sam gets the following marks in two of his subjects:

Biology 100

Mathematical Methods 80

As Sam gets a lower mark compared to Bob in the common subject (Mathematical Methods) that they share, his 100 for biology is considered not as difficult to achieve as Bob's 100 for Specialist Mathematics.  As a result, Biology would get scaled lower compared to Specialist Maths.

The method for scaling is far from perfect, particularly when it comes to accurately determining the difficulty level of languages that have significant numbers of native speakers present in the state.  Consider the following two students:

Joe gets the following marks in two of his subjects:

Biology 100

English 70

Mengyin gets the following marks in two of his subjects:

Chinese 100

English 40

Mengyin scored much lower than Joe in their common subject (English).  Therefor the scaling system would infer that a 100 in Chinese is worth less than a 100 for Biology.

What Queensland subjects scale the highest?

The subject scalings change slightly from year to year. The QCAA summarises the scalings each year in their ATAR report.  The Queensland ATAR system is very new, as a result there are only three years of data.  The documents are below:

After combining the data from the above 3 reports, general trends about what subjects consistently scale high can be observed.  The top 10 subjects for scaling in order are as follows:

As mentioned earlier, the above explanation is very simplified.  Full details of the process can be found in the technical document.  Please be warned, it is quite an intense read. 

Calculating my ATAR in Queensland

Below is an app that a former student wrote and has kindly let me embed in the site. It allows you to explore subject scaling and even get an estimate of your ATAR score.  However, as both subject scaling and the conversion from the Tertiary Entrance Aggregate (TEA) to the final ATAR score changes every year, it should be used as a general guide only.