Scaling

Your SACE/NTCET results cannot be used directly in the selection process for university or TAFE SA courses. A mathematical process called scaling must first be used to ensure that results obtained in different subjects can be directly compared. The results must also be converted to numerical values to allow a university aggregate to be calculated. 

SATAC has produced a 10 minute video, along with the information below, to explain the scaling process and tertiary selection.

The need for scaled scores

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. 
The numeric measures of your performance in each of your individual subjects are called scaled scores. The scaled scores are then added up according to certain rules to create numeric measures of your performance across all of your subjects. These are called the university aggregate and the TAFE SA Selection Score. 

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.

Raw scores

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.

Calculating the raw score for scaling (393kb PDF)

Scaling

Every SACE/NTCET subject is unique; it has its own curriculum, learning goals and assessment criteria. The average level of 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. These factors mean that a straight comparison of subject raw scores can be misleading. 

We can safely assume that a Biology raw score of 11.2 is a better result than a Biology raw score of 10.8, but we can’t assume that a Biology raw score of 11.2 is a better result than a Maths raw score of 10.8. In Maths, 10.8 might be an above average score, while in Biology 11.2 might be a below average score.
Scaling is the process by which we adjust the raw scores for a given subject to allow the results for that subject to be fairly compared with the results of any other subject.

How does scaling work?

When you complete a subject we use the results of the individual assessment components to derive your raw score.

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. This information, however, doesn’t allow us to compare your performance with students who’ve completed other subjects. 

To work out if your raw score of 10.4 in Biology is equivalent to another student’s raw score of 10.4 in Modern History (a subject you haven’t taken), our starting point is to look at the subject scores for all SACE students who’ve completed both Biology and Modern History. If the average raw score of these students for Biology is 10.0 and for Modern History is 10.8, we can reasonably conclude that a Biology score of 10.4 is a better achievement than a Modern History score of 10.4. 

You can see from this example that this simple logic allows us to understand what is the better achievement for this pair of results. 

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) and a TAFE SA Selection Score - our numeric measures of your academic performance.

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 2015 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. 

SATAC accepts no responsibility for any misuse of these data.

2015 Scaled score outcomes
Overall grade Maximum Minimum Average
A+ 20.0 18.2 19.53
A 19.6 15.4 18.27
A- 18.6 13.2 16.87
B+ 17.8 10.6 15.39
B 16.6 8.6 13.90
B- 15.4 8.0 12.47
C+ 14.6 6.8 11.06
C 13.2 5.6 9.79
C- 12.0 4.8 8.67
D+ 10.8 4.2 7.52
D 9.2 3.2 5.95
D- 7.8 2.6 4.47
E+ 6.2 1.4 2.78
E 4.6 1.0 1.43
E- 2.4 0.6 0.53

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 and TAFE SA Selection Score. 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 0.05 rather than 0.2 as previously reported.

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. 

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