How is Your ATAR Calculated?

Since 50% of your final mark comes from school assessments, many problems arise due to comparison:

1. How do we fairly compare between schools?

2. How do we compare one cohort with another? E.g. 2024 vs 2022 cohort.

3. How do we compare different subjects with different difficulties? How do we compare a 95/100 in 2U maths with the same mark in 4U maths?

The first 2 problems are dealt with by NESA* through processes known as “moderation” for problem 1 and “alignment” for problem 2, together known as “mapping”. School teachers and students normally do not get to see this process.

The 3rd problem is dealt by the UAC* through “scaling”.

*See appendix.

The school marks NESA receives are submitted by the school teacher, which creates a problem of subjectivity. NESA only considers the rankings provided by the raw marks, as well as the size of the gap between consecutive marks. The raw mark is then replaced by another mark called the “school moderated assessment mark”.

This moderated mark comes from the final HSC exam. NESA arranges all the students’ marks from each school in ranked order and assigns each external mark to the same school rank. NESA then adds up the total mark of a cohort to compare between schools.

People from NESA (known as “judges”) who are very experienced and have a comprehensive understanding of the standard for each subject separate a cohort’s raw HSC exam marks for each subject into “bands”. The top performing band is Band 6, which means your aligned mark is within 90-100 inclusive. These bands are used to compare between different cohorts. For example, the 2023 cohort may have been pretty smart and received 99 as their top exam mark, which aligns with Band 6. Meanwhile, the 2024 cohort only received 80 as their top exam mark, which is only a Band 4 after alignment.

Note that extension subjects only have 4 different bands instead of 6, with the highest band being E4.

During scaling, UAC considers how well a student does in all their subjects. If a student is consistently getting lower marks for every subject, but high in one subject, there are 2 explanations:

1. The test for that one subject was relatively easy.

2. The student is a prodigy in one field.

It seems unreliable to assume the first explanation based off one single student, but the UAC take a large sample size of all the students, the assumption becomes valid. For example, if a lot of students performed poorly in all their subjects besides drama, this indicates that drama had a relatively easy test.

Before the ATAR is calculated, you are assigned a number called an “aggregate”. Students do not normally have access to their aggregate. The aggregate is out of 500 and is the sum of the scaled marks of your 10 best units (including your 2 best units of English, since English is compulsory 🙁). Finally, your ATAR is calculated using your aggregate by looking at the percentage of students who achieved the same aggregate as you, or better.

You must complete at least 4 different subjects to be eligible for an ATAR, although your aggregate can be based on fewer subjects depending on individual performance.

The ATAR is not a score, but rather a percentile position out of all the students in your cohort. An ATAR of 80 means that you are in the top 20% of the entire state for your year group. Similarly, an ATAR of 99.95 means that you outperformed 99.95% of your year group.

Consider the Atlas Academia High School 2024 cohort with only 4 students.

1. The raw marks of each subject are ranked and the gap between each mark is calculated.

2. The students sit the final HSC exam. Their marks from this exam are put in ranked order as well, and then assigned to the corresponding school rank. This is known as the school assessment moderated mark.

Note:

• If there are multiple people tied for the same rank, they will receive the same moderated mark.

• If multiple people achieve the same external HSC mark, multiple corresponding ranks will receive the same moderated mark.
  

3. The total mark of each school is calculated and compared with one another.

• The final mark may show NESA that the Atlas Academia students are much smarter than the rest of the state, which the school assessments could not reveal.

  • Hot tip: This is why the cohort needs to work together for the final exam, and the reason why students in selective schools typically gain a big advantage.

4. The final HSC mark for each subject is calculated from the average of the 2 marks. Students retain their individual external marks.

Summary of the above processes:

5. The raw exam marks are aligned into appropriate bands by “judges”.

6. The HSC marks are scaled according to relative difficulty.

7. Taking the 10 best units, the individual marks are added up to form an aggregate after scaling.

8. Finally, your ATAR is calculated from the aggregate!!

• Your final ATAR is your rank across the whole cohort, calculated from your 10 best units, including 2 units of English.

• The HSC mark for each subject is the average of your internal and external marks.

• School marks are only used to provide ranks and relative gaps. They are replaced by the moderated mark, which comes from the cohort’s external exam marks.

• Your external mark for each subject is your scaled, final HSC exam mark.

The New South Wales Education Standards Authority (NESA) gives input to the NSW teaching workforce by developing school curriculum, teaching, assessment, policies and registration. NESA was originally known as the Board of Studies (BoS) before 2017, so if you see anything referring to the BoS, it is analogous to NESA.

The Universities Admission Centre (UAC) processes applications for undergraduate university courses in NSW and the ACT. They are a separate group to NESA. You must pay an $80 fee (early bird price) for undergraduate university applications. The UAC is also separate from other states (e.g. VTAC for Victoria and QTAC for Queensland), which means that you need to pay a separate registration fee if you plan on applying for universities in other states ☹️. If you apply for postgraduate degrees later down the line, you will most likely also do it through UAC.

Eddie Woo's 3 part Youtube series on HSC marks:

https://www.youtube.com/watch?v=7InJg8hyty4

https://www.youtube.com/watch?v=J-7qZ6iPZ10

https://www.youtube.com/watch?v=kZlaqG9t4Qo

Official UAC website:

https://uac.edu.au/future-applicants/atar