New to ATAR, moderation and scaling?

In this blog, we explain how your ATAR is calculated and how your results are adjusted along the way to give a fair reflection of your performance in comparison to your state-wide peers. Our next blog will cover strategies you can implement to maximise your subject ranks and ATAR result.

The ATAR is a rank between 0 and 99.95 that describes a student’s academic performance relative to all the students who started high school (Year 7) with them.

An ATAR of 96.00, for example, indicates that you performed as well as, or better, than 96% of the students who started high school (Year 7) in the same year as you, regardless of whether they moved interstate, or left school before completing Year 12.

ATAR’s are reported in increments of 0.05.

The ATAR was developed for the sole purpose of tertiary selection, and is calculated by VTAC using the scaled study scores for:

  • your best score in any one of the English studies, plus
  • the scores of your next best three permissible studies (which together with the English study make the ‘Primary Four’), plus
  • 10 per cent of the scores for any fifth and sixth study which you may have completed (these are called increments).

A maximum of six results is used to calculate the ATAR. If you have more than six results, the six permissible scores that give the highest ATAR are used.

Graded Assessments, Ranks & Study Scores

Graded Assessments

All VCE studies have three graded assessments for each Unit 3 and 4 sequence. One graded assessment will be for Unit 3 coursework (SACs), which is assessed by your teachers at school. The second graded assessment is for Unit 4 coursework (also assessed by your teachers) whereas the third graded assessment is the external exam. Scored VCE VET studies have two graded assessments for each Unit 3 and 4 sequence. VCAL units do not have graded assessments.

SACs and Ranks

Which SACs you have to complete depends on the subject and your teacher

i.e. these assessments vary across the state. As there are differences in school marking and assessment difficulty, school marks are adjusted to be on the same scale as the exam marks (moderation).

Your SAC marks are used to determine your relative position or rank in each subject at your school.

The student who obtained the highest SAC marks in a subject will receive the highest rank of 1. The student who obtained the fifth highest SAC marks in a subject will be ranked as number 5. These rank orders are used to determine the moderated SAC marks, which are used to calculate your study scores.

External Assessments

As there are differences in exam difficulty from year to year, examination marks are modified to a predefined distribution (standardisation).

Study Scores

The graded assessments in a subject are added together by VCAA in a defined ratio to produce a raw study score.

A study score indicates how you performed in a study in relation to all other students who took the same study.

The raw study score is a number between 0 and 50 with mean 30 and standard deviation 7 and is distributed according to the properties of a normal distribution curve.

Note that a 45 study score is not equal to a mark of 90%. A 45 study score indicates that you’re in the top 2% of the state.

As there are differences between subject difficulty, study scores are scaled (scaling).

Scaling of Study Scores

Before study scores can be used to calculate an ATAR, they are scaled by VTAC to adjust for the fact that it’s harder to obtain high marks in some studies than others. Fair comparisons can then be made about students’ achievements, regardless of which courses they decided to study.

The scaled study scores for the Primary 4 subjects and any available increments are added together to produce an aggregate score.

Students are then ranked in order of their aggregate, and a percentage rank is assigned to distribute students as evenly as possible over a 100-point scale. The top 0.05% scorers are awarded a 99.95 ATAR, the next 0.05% highest scoring students are awarded a 99.90 ATAR and so on.

Using Scaling to Your Advantage

“If you are not good at a subject then scaling won’t save you. But if you have any capability for more challenging subjects then please stick with them because the scaling will benefit you.” Statement made by an undisclosed private school to their students

Scaling is only relevant if you receive the same mark in every subject and you dedicate the same amount of time to each subject OR you find all subjects equally easy/difficult.

So if you’re good at multiple subjects and enjoy studying them, choose the subjects that scale best. Otherwise, choose the subjects that you’re good at or that are of interest to you.

Moderation of Assessment Marks

Depending on which school you attend, the SACs you complete may be easier or harder than those set by other schools.

In a school where SACs are easier, students would receive higher marks than they would in a school where the SACs are more difficult. If a teacher is a hard marker, students would get lower marks for the same standard of work than they would in a school with generous markers.

If these differences in marking and SAC difficulty aren’t taken into account, many students wouldn’t receive fair study scores. VCAA therefore effectively calculates what each student’s school-based assessment mark (the sum of your SAC marks in a Unit 3/4 study) would be if every student had the same marker, and the same SACs were used across the state. This is done by comparing each school’s assessment marks with a common scale, which is the external VCE exam(s) that every student sits at the end of the year. This process is called moderation.

Statistical moderation realigns the level and spread of each students’ assessments in a study at a school, to match the level and spread of the same students’ scores on the common external VCE exam. This is done without changing the rank order of students within that course group i.e. If you were awarded the highest rank in a study then you will receive the highest moderated assessment mark.

The moderated assessment mark is then added to your standardised examination mark to produce the study scores that are used to calculate your ATAR.

A Closer Look at the Moderation Process

Step 1:

Your teacher in each subject submits the final assessment mark for each student, as well as the rank order of students with the relative gaps between them to VCAA.

Step 2:

After each VCE exam, an external score is calculated for each student at a school.

Step 3:

The assessment marks submitted by a school in each subject are moderated to that school’s total VCE examination marks.

  • The total of the moderated assessment marks obtained at a school in a particular course is adjusted to equal the total of the examination marks obtained by that same school, except where some students may have been initially excluded from the moderation process.For example, if you added every students’ exam mark in a subject together and you obtain a score of 890, then all of the moderated school assessment marks in that same subject will be assigned in such a way that they also add up to equal 890.
  • The median of the moderated scores (the middle score when results are organised from highest to lowest) is made equal to the median of the external scores.
  • The quartiles (25% and 75% positions) of the moderated scores are made equal to the quartiles of the external scores.
  • The highest assessment mark is adjusted to equal the highest examination mark, regardless of what mark that student received in the external exam. For example:

    You obtain an average of 90% for your SACs but your rank in the subject is 1. This means that you’ll receive the highest moderated assessment mark (which is equal to the highest examination mark).You obtain 82% for your examination mark.Another student at your school obtains the highest examination mark of 97% in that subject. You will therefore receive a score of 97% for your moderated assessment mark.Your examination mark will be what you actually scored = 82%.For example:You obtain an average of 90% for your SACs but your rank in the subject is 1. This means that you’ ll receive the highest moderated assessment mark (which is equal to the highest examination mark).You obtain 82% for your examination mark.Another student at your school obtains the highest examination mark of 80% in that subject. You will therefore receive a score of 80% for your moderated assessment mark.

    Your examination mark will be what you actually scored = 82%.

    This example clearly shows how important it is for the high achieving students to get the highest possible examination marks.

  • The lowest assessment mark is usually adjusted to equal the lowest examination mark, regardless of what mark that student received in the external exam. For example:You obtain an average of 50% for your SACs and you have the lowest rank in that subject.You obtain 78% for your examination mark.The lowest examination mark obtained in that subject at your school is 70%. You’ll therefore receive a score of 70% for your moderated assessment mark.Your examination mark will be what you actually scored = 78%.This example highlights how important it is for the weakest students to get the highest possible examination marks.
  • The remaining students obtain a moderated assessment mark in accordance with their rank and the relative gaps that exist between assessment marks. This means that the student who obtained the third highest assessment mark will receive the third highest moderated assessment mark and so on.

Step 4:

The moderated assessment mark is then added to your standardised examination mark to produce the study scores that are scaled, and then used to calculate your ATAR.

Moderation Example

The top diagram shows the marks obtained in a certain subject in the external exam (after standardisation).

The middle diagram shows the overall assessment marks (derived from the SACs) given to the students studying a particular subject. Note that the students obtained higher marks in their internal assessments as compared to the external exam. This suggests that the SACs given to students were too easy or that the teacher is a generous marker. If these differences between the internal and external assessments aren’t taken into consideration, the students in this subject will obtain higher study scores than other students of the same academic level.

The bottom diagram shows the effects of the moderation process. The level and spread of each students’ school assessments is aligned to match the level and spread of the same students’ scores on the common external VCE exam. Every students’ assessment mark will therefore decrease.

Note:

  • Although the moderation process may change a student’s school based assessment mark, it has no effect on that student’s rank order given by the school. This means that the student who initially obtained the highest school based assessment mark will receive the highest moderated score.
  • The moderation procedure is not influenced by students with anomalously low external performance, or by students who did very poorly on the school assessment but very well on the external assessment.

Implications of Moderation

  • Your school course group’s performance in the external exam will determine your moderated assessment mark for that course.
  • Statistical moderation can result in the internal school SAC grades either increasing or decreasing.
  • In most cases, another student’s examination mark will become your moderated school based assessment mark. Therefore, the Year 12 students at your school should be working together to make sure that everyone performs to the highest possible standard in the exams.
  • The moderation process will work in more students’ favour when the difference between the highest and lowest examination mark is as small as possible. Students should therefore be helping the weaker students achieve the best possible marks in their exams.
  • The students who are awarded the highest VCE marks are those who achieve examination marks that are close to, or better than, their school-based assessment marks.