Scaling is a mathematical process which provides the basis for comparing student performance in different SACE/NTCET Stage 2 subjects.
Every SACE/NTCET subject is unique; it has its own curriculum, learning goals and assessment criteria. The average ability of students will often vary from one subject to another, and this will impact on the overall pattern of marks awarded in each subject.
Scaling allows us to compare the performance of students in all SACE/NTCET subjects and in all combinations of subjects.
SATAC has produced a 10 minute video, along with the information below, to explain the scaling process and tertiary selection.
We have also answered a range of frequently asked questions about scaling.
How does scaling work?
Scaling adjusts the ‘raw scores’ of a subject, to allow the results for that subject to be fairly compared with the results of any other subject. Raw scores are the results of the individual assessment components of a subject.
For example, you may have a raw score of 10.4 in Biology. This tells us where you sit in relation to other Biology students, but it does not allow us to compare your performance in Biology with students who completed different subjects to you.
By applying scaling to your raw scores in Biology, we can fairly compare your achievement in this subject to the achievement of another student in Modern History, or English, or Mathematics and so on.
There are thousands of possible combinations of subjects completed by SACE/NTCET students. Scaling ensures that you are neither advantaged nor disadvantaged by choosing one combination of subjects over another.
Scaling allows us to compare all results by applying this logic to all possible pairs of results for all students. It is actually a mathematical process that adjusts scores called the South Australian Logistical Scaling Procedure. The Scaling Procedure is owned and defined by the universities.
The process of scaling is overseen by South Australia’s Scaling Monitoring Committee which includes membership from the universities and TAFE SA who own the scaling process, as well as representatives from the three schooling sectors.
The end results are scaled scores for each subject that can be fairly compared with the scaled scores of any other subject.
This process doesn’t in any way enhance or diminish your performance in each of your subjects. Your ranking relative to other students in those subjects does not change. Scaling has simply allowed us to compare performances across all subjects.
During the process we take the opportunity to convert the final scaled scores to be out of 20.0 for 20 credit subjects and out of 10.0 for 10 credit subjects – this is done to emphasise that scaled scores stem from a different philosophy from your grades and raw scores.
The scaled scores we get from this process are then used to produce a university aggregate (and from that an ATAR) - our numeric measures of your academic performance.
Why is scaling used?
When considering applications for tertiary entry the institutions prioritise their offers in order of academic merit. The most useful way of defining academic merit is to produce numeric measures of your performance.
Scaled scores, not subject results, are used to produce a university aggregate (from which an ATAR is derived).
It’s important to remember that the scaling process doesn’t in any way enhance or diminish your performance in each of your individual subjects. Scaling has simply allowed us to fairly compare the performance of different students across different subjects.
When choosing your subjects
You should choose subjects which best align with your interests and abilities, rather than on the basis of past scaling outcomes (which can vary from year to year).
It is far more important to consider how well a subject matches with your skills, interests, abilities and life goals than whether it is traditionally ‘scaled up’ or ‘scaled down’. Choosing subjects based on historical scaled scores is likely to result in a worse university aggregate and ATAR.
The purpose of scaling is to reflect the true academic ability of a student no matter which subject they choose.
Calculating scaled scores
Your achievement in each of your SACE/NTECT Stage 2 subjects is expressed as a grade in the range A+ to E-, and behind these grades are results for each of the assessment types of each subject. To create scaled scores for the subjects that you attempt using these results, two things need to happen:
- these results need to be converted into a numeric equivalent (called a raw score); and
- these numeric equivalents need to be made comparable through a process called scaling.
Your overall subject grade is not used to create a raw score. Instead, the A+ to E- grades for your achievements in each of the school assessed components of a subject are used, as well as the numeric result of the externally assessed component (e.g. examination, investigation).
Raw scores are on a scale of 0 – 15.0 with a decimal place. Where a subject has a school assessed component of 70%, its contribution to the raw score is out of 10.5 (70%) and therefore the externally assessed contribution is out of 4.5 (30%).
For more information on how a raw score is calculated read our fact sheet below.
Scaled scores for A+ to E- grades
So that students, parents and teachers can have some context regarding the relationship between the A+ to E- grades and scaled scores, the Scaling Monitoring Committee has provided SATAC with a summary of scaling outcomes for 2018 in the table below.
It shows the maximum, minimum and average scaled scores attained across all 20 credit Tertiary Admissions Subjects (TAS) for each grade.
Because the scaled score is derived from the results from the individual assessment components, two candidates with the same grade (e.g. B+) in the same subject will get different scaled scores. Actual scaled score outcomes vary greatly from subject to subject. Scaling outcomes by subject are not available publicly.
Students, parents, schools and educational professionals should note that these data cannot be used accurately to predict ATAR outcomes for individual students. Any ATAR outcomes suggested by such use of these data should not be trusted.
Students are advised to choose subjects which best align with their interests and abilities, rather than on the basis of past scaling outcomes (which can vary from year to year).
SATAC accepts no responsibility for any misuse of these data.
|2018||Scaled score outcomes|
Scaling operates in the background to ensure that students can choose subjects with the assurance that differences in subject objectives, content and assessment practices are accounted for when subject results are used in the calculation of the university aggregate. The universities and TAFE SA do not publish the scaling outcomes of individual subjects.
Granularity of scaled scores
From 2017, subjects undertaken by SACE/NTCET students will use smaller scaled score intervals. From the 2017 cohort, Tertiary Entrance Statements for SACE/NTCET candidates will report scaled scores for 20 credit subjects in intervals of 0.1 rather than 0.2 as previously reported. The scaled scores for 10 credit subjects will be reported in intervals of 0.05.
The main benefit will be ATARs that more precisely reflect the academic potential of candidates. This will be brought about by a stronger alignment between ATARs and the subject achievements that underpin them.
The outcomes of scaling to a finer degree:
- the new system will be fairer
- in contrast with past practice, candidates performing slightly better in the publicly assessed component of a subject will receive slightly better ATARs than was previously the case
- the new system will enable SACE/NTCET students to compete more fairly for high demand courses interstate
- the universities will continue to explore means of selecting students that involve criteria other than the ATAR; however, where the ATAR is used, its ranking will be fairer for all candidates
Please note, there will be no retrospective calculations for subjects studied prior to 2017. SACE/NTCET results from 2011 to 2016 inclusive will use scaled scores in 0.2 or 0.1 intervals depending on whether the subject is 20 or 10 credits.