How your ATAR is calculated

There are over 25,000 different patterns of study completed by ATAR students. Given the choice available, your rank in different courses will not necessarily have the same meaning. A good rank is more difficult to obtain when you are competing against students of high academic ability.

The underlying principle of scaling is that you should be neither advantaged nor disadvantaged by choosing one pattern of study over another. The scaling algorithm estimates what your marks would have been if all courses had been studied by all students and all courses had the same mark distribution.

How scaling works

Just as individual units of different currencies are not of equal value (£1 is not the same as $1), marks in different courses can’t be compared because the courses are completely different. But just as exchange rates allow us to compare the value of different currencies, the scaling process allows us to compare marks in different courses properly and fairly.

Courses are scaled so that the mean and distribution of the marks obtained in the course are consistent with the mean and distribution of marks that the students taking that course obtain in all of their HSC subjects.

This means that courses that are taken by many students with high levels of achievement in all their courses (as is usually the case for courses such as Mathematics Extension 2 and Physics) award a higher proportion of high scaled scores than courses that are mainly taken by students with an average level of achievement across all their courses. However, even in subjects that have a high proportion of high scaled scores, you still need to achieve a high HSC mark in order to obtain a high scaled score.

Your scaled marks, not your HSC marks, will be used to calculate your ATAR; high HSC marks do not always translate to high scaled marks. In fact, for most courses, your scaled mark will be lower than your HSC mark.

Your scaled mark in a course will be influenced by your position in the course and the scaled mean for that course. The example below shows the HSC and scaled marks of a student who achieved results in the 90th percentile for each course.

Even though the HSC mark for Ancient History was not the lowest, it won’t be included in the ATAR calculation. This is because in NSW the ATAR is calculated from 2 units of English (even if they are your lowest units, as in this example) plus the next best 8 units (to make 10 units in total), and in this example, Ancient History has the lowest scaled mark of all the courses (apart from English). Scaled marks are not reported to students.

If you wish, you can complete a 2-unit course one year and the corresponding extension course in a later year. If you withdraw from the extension course, the marks from the 2-unit course that you have already completed will be available for inclusion in the calculation of your ATAR.

However, an extension course generally cannot contribute to the ATAR if the corresponding 2-unit course has not been satisfactorily completed.

English extension courses

The unit value of the courses always stays the same regardless of whether you complete the courses in one year or over two or more years.

• English Advanced = 2 units
• English Extension 1 = 1 unit
• English Extension 2 = 1 unit

The two (or three) courses are available for inclusion in the calculation of the ATAR. The course/s with the highest scaled marks will be used first to satisfy the best 2 units of English requirement.

You must complete English Advanced to count English Extension 1 (and you must complete English Extension 1 to count English Extension 2).

Mathematics extension courses

Up to 4 units of calculus-based maths can be included in the ATAR calculation. Mathematics Extension 1 has a different weighting (in terms of units) depending on whether it is paired with Mathematics Advanced or Mathematics Extension 2.

If you study Mathematics Advanced, then Mathematics Extension 1 accounts for 1 unit.

If you study Mathematics Extension 2 (2 units), then Mathematics Extension 1 accounts for 2 units. This is calculated by doubling the mark received for the 1-unit course.

You can complete Extension 1 and Extension 2 without completing Mathematics Advanced (but you must complete Mathematics Extension 1 to count Mathematics Extension 2).

If you do complete Mathematics Advanced then go on to satisfactorily complete Mathematics Extension 1 and Mathematics Extension 2, your results in Mathematics Advanced will not be included in the ATAR calculation, even if you have excelled in it.

Your ATAR is based on the aggregate of scaled marks in 10 units, irrespective of the year in which the courses are completed. This means that, subject to the approval of your school, you can accumulate courses for the ATAR over a period of up to five years, or you can accelerate your studies by attempting HSC courses while in Year 11.

The five-year period is a ‘rolling period’; if you wish to go beyond the five years, your ATAR is based on your marks from the most recent five years.

Scaled marks are calculated in the year the courses are completed.

You are considered to be repeating an HSC course if you:

• repeat the same course
• study a different course in the same subject area, apart from an extension course.

Within a five-year period there are no restrictions on the number of times you can repeat a course. If you repeat a course, only the marks for your latest satisfactory attempt will be available for inclusion in the calculation of your ATAR, even if they are lower than your earlier attempt.

For example, if you studied Biology in 2023 and you repeat Biology in 2024, only your 2024 Biology marks will be available for inclusion in the calculation of your ATAR in 2024 even if they are lower than your 2023 Biology marks.

If you enrol in a repeat course and then withdraw, either officially by advising your principal or the NSW Education Standards Authority (NESA) or unofficially by non-attendance at the examination, you'll be considered as not having completed the course and it will be regarded as a non-satisfactory attempt. In this case, the marks from your previous satisfactory attempt in the course will be available for inclusion in the calculation of your ATAR.

You can withdraw from a repeat course at any time up to and including the HSC examination, but you should notify your principal or NESA of your withdrawal.

Your most recent ATAR will be the one used by tertiary institutions for selection purposes.

Repeating a component of a subject that has an extension course

If you repeat a subject or a component of that subject such as an extension course, the marks for the repeated component of that subject will be available for inclusion in the calculation of your ATAR.

For example, if in 2023 you studied 2-unit Modern History and the History Extension course, in 2024 you could repeat:

• just the 2-unit course
• just the extension course
• both the 2-unit and the extension courses.

In the first case, you would keep your 2023 mark in the extension course. Your 2-unit mark from 2023 would be replaced by the 2-unit mark achieved in 2024.

In the second case, you would keep your 2-unit mark. Your 2023 mark in the extension course would be replaced by your 2024 extension mark.

In the third case both marks would be replaced by the marks gained in 2024.

Studying a different course in the same subject area

A different course in the same subject area is considered to be a repeat course and completely replaces the previous course in the calculation of the ATAR.

The repeat course may have a different unit value from the previous course.

For some subject areas the NESA rules on repeating are complex. It is essential that you consult with your school to determine the impact of repeating a course or replacing one course with another.

For example, if you study a beginners language course and the following year complete the continuers language course in the same language, the mark in the continuers language course replaces the mark in the beginners course.