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.
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"
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%).
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,
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
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
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
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
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
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
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
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
you would remember her raw score before scaling was
After scaling it might become
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
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
Average scaled score for a 20 credit tertiary
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