SATAC Home

   Terminology

   TAFE SA Entry

   University Entry

   Recognised Studies

   Scaling

Scaling

To understand the scaling process you can view SATAC's 10 minute YouTube video here and/or read the information on scaling on this page.

Play


Scaled scores and how they are calculated

The need for scaled scores

When considering applications for entry to tertiary studies 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 across all the subjects that you attempt (the ATAR and TAFE SA Selection Score) so that applicants can be ranked in order of these measures.

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 derive the ATAR and the TAFE SA selection score.

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 (e.g. the ATAR) 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"


The numeric equivalent – the "raw score"
 

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 full details on how your raw score is calculated
follow the story of how we calculate the raw score for a mythical student Jane in her subject Information Technology by clicking here.



Making the raw scores comparable: scaling  

Scaling is the process by which we adjust the raw scores you get for your SACE/NTCET subjects to give a clearer picture of your overall SACE/NTCET achievement compared to other students.

Your raw scores are an excellent indicator of your achievement in any given subject relative to other students in the same subject, but are less useful as a means of comparing your overall SACE achievement in your best 80 credits of subjects to other students, the majority of whom will have studied different subjects.

Every SACE 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 enables us to produce numeric measures of achievement that are comparable across all subjects so that these measures can be added together fairly and with meaning. 


How does scaling work?

If you’ve completed four SACE subjects, we use the results of the individual assessment components to derive four bits of information about you:

  • your score of 10.4 in Biology tells us where you sit in relation to other Biology students

  • your score of 8.6 in English tells us where you sit in relation to other English students

  • your score of 11.0 in Art tells us where you sit in relation to other Art students

  • your score of 9.8 in Maths tells us where you sit in relation to other Maths students.

From this information we can easily assess your overall achievement relative to students who’ve completed exactly the same subjects as you. We can simply add up your overall points and see how your total compares. This information doesn’t, however, allow us to compare your performance with students who’ve completed a different combination of SACE subjects.

To work out, for example, if your raw score of 8.6 in English is equivalent to another student’s raw score of 8.6 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 English and Modern History. If the average raw score of these students for English is 8.2 and for Modern History is 8.6, we can reasonably conclude that an English score of 8.6 is a better achievement than a Modern History score of 8.6.

You can see from this example that by applying some simple maths, we are able to deduce a small piece of information about your overall performance relative to (some) other students that wasn’t previously available to us.

When we scale, we simply apply the same maths to all students and to all possible combinations of SACE subjects. There are thousands of these combinations, and we therefore generate a great deal of quite specific information about the relative performance of students in subjects across the board. Very clear patterns of data emerge which make it possible for us to determine accurately where a score in one subject sits relative to a score in another subject. We then use this data to adjust all students’ subject scores as necessary to present an accurate picture of each student’s overall achievement relative to other students. 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 simply allows us to compare performance across all subjects.

During the process we take the opportunity to convert the final scaled scores to be out of a different number (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 used to produce a university aggregate and from that a Australian Tertiary Admission Rank (ATAR) (for university admission) and a TAFE SA Selection Score (for admission to TAFE SA courses at certificate IV and above).


The Scaling Process and Final Calculations

Once the raw scores have been determined they are scaled using the South Australian Logistical Scaling Procedure defined by the univerities. If you followed the story of how we calculated the raw score for Information Technology for our mythical student Jane, you would remember her raw score before scaling was 9.655/15.0. After scaling it might become 10.135/15.0.

As Information Technology is a 20 credit subject, this scaled value is converted to a 20 point scale by simply multiplying it by 20 and dividing by 15:

10.135 X 20 15 = 13.51333

Scaled scores for 20 credit subjects are reported to the nearest 0.2 interval, so Jane’s final scaled score for Information Technology is 13.6

Scaled scores for 10 credit subjects are reported out of 10 to the nearest 0.1 interval.

The university aggregate (and hence the ATAR) and the TAFE SA Selection Score are then calculated using the best possible combination of these scaled scores under the new rules which are described in SATAC’s Tertiary Entrance Booklet.


Scaled scores for A+ to E- grades

So students, parents and teachers can have some context regarding the relationship between the A+ to E- grades and scaled scores, South Australia’s Scaling Monitoring Committee (which includes membership from the universities who own the scaling process) has provided SATAC with a summary of scaling outcomes for 2012 in the table below.

It shows, for each grade in the A+ to E- range, the average scaled score attained across all 20 credit Tertiary Admissions Subject results. 

It is intended to be a guide to what was a “reasonable” outcome of the scaling process.  Please note it is not what candidates should expect their actual scaled scores to be. 

Actual scaled scores will be higher or lower according to the subject attempted.  Also, because the scaled score is derived from the results from the individual assessment components, two candidates with the same grade (say, B+) in the same subject will get different scaled scores.  This might be because the numerical contribution of the externally assessed component might be different, or the candidate whose underlying results were B+/B/B-/A- will have a different raw score from the candidate who had B-/B/B+/A- due to the varying weightings of the assessment components.

Grade level

Average scaled score for a 20 credit tertiary admissions subject

A+

19.65

A

18.50

A-

17.16

B+

15.78

B

14.34

B-

12.95

C+

11.60

C

10.25

C-

9.05

D+

7.63

D

5.98

D-

4.34

G

3.21

E+

2.99

E

1.70

E-

0.90

Please note the universities and TAFE SA do not publish the scaling outcomes of individual subjects. 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.



< Back