ATAR Scaling by the Numbers: Rank Beats Scaling, Except in the Top Maths Courses

Somewhere in Year 10 or Year 11, most students hear that the subjects they pick now will quietly raise or sink their ATAR, and that some choices are traps. The official numbers tell a calmer story. Scaling adjusts for the strength of the students who sit a course, not for how hard its content is, so the scaled mark a student ends up with depends mostly on where they rank inside that course. Our position follows the two admissions centres that run the calculation: choose subjects on ability, interest and prerequisites. There is one real exception, and the 2025 tables show it clearly. Students who genuinely belong in the top maths courses do gain from them.

What scaling is, in two systems

The mechanics differ by state, and only two sets of figures appear in this article.

In New South Wales, the Universities Admissions Centre (UAC) builds the ATAR from a student’s best 10 units, which must include two units of English, and each unit carries a scaled mark out of 50. UAC notes that for most courses the scaled mark will be lower than the HSC mark, and that scaled marks are not reported to students at all, which is why so many students compare the wrong numbers when results arrive. In Victoria, the Victorian Tertiary Admissions Centre (VTAC) converts each study score to a scaled score between 0 and 55, then adds the top four scaled scores, one of which must be an English, to 10 per cent of the fifth and sixth. Queensland, South Australia, Western Australia and the ACT run their own calculations through QTAC, SATAC, TISC and BSSS, and their own publications are the place to look.

The common thread is that the ATAR is a rank, not a score. A rank behaves differently from a fixed line. A threshold like the 75 per cent pass mark on the Australian citizenship test can be cleared by every candidate in the room at once; an ATAR places each student relative to everyone else in their age group, so it cannot be earned by choosing a subject with a reputation. It is earned by placing well.

The check: when a predicted mark comes back from school, ask whether it is an HSC mark, a study score or a scaled figure, because the three are not interchangeable.

Why your rank sets the scaled mark

UAC puts the principle in a single sentence: “Your scaled mark in a course will be influenced by your position in the course and the scaled mean for that course.” Both parts matter, and the second is the one that gets all the attention. The first is the one a student controls.

The table below is drawn from UAC’s Table A3 for the 2025 HSC. Each figure is a scaled mark on a 1-unit basis, out of 50. P90 is the scaled mark of a student who placed ahead of 90 per cent of that course’s candidates; P50 is the middle of the course; P25 is a quarter of the way up.

Read across any row and the spread inside a course is wider than the gap between most courses. Business Studies runs from 15.1 at P25 to 39.2 at P90, a range of more than 24 marks, while the difference between its scaled mean and Biology’s is 2.3.

Two limits apply to this table, and UAC states the first itself. Table A3 “should not be used as a simple HSC to scaled mark conversion table”; its primary purpose, in UAC’s words, “is to show the relativities between courses.” The second is that these are 2025 figures, produced by the 2025 cohort, and no table published today can say where a student sitting the HSC in 2027 will land.

The check: find each subject on a shortlist in the table and note how far apart its P50 and P90 sit. That gap is the reward for ranking well, and it is usually larger than any reputation the subject carries.

Three worked examples from the 2025 tables

The students below are hypothetical, invented for illustration. The figures are from the official 2025 tables.

Student A, NSW. Say Student A could realistically finish near the 90th percentile in Business Studies but would sit around the middle of Mathematics Advanced. In Business Studies the P90 scaled mark was 39.2; in Mathematics Advanced the P50 was 33.2. Playing to strength is worth 6.0 scaled marks per unit, and if a middling rank in Advanced slipped to the 25th percentile (25.9), the gap widens to 13.3 per unit. Both are 2-unit courses, so the difference counts twice in the aggregate. On these numbers the “low-scaling” choice is the stronger one for this student, because rank outweighs reputation.

Student B, Victoria. The VTAC 2025 report shows a study score of 40 in Business Management scaling to about 38, and a study score of 25 in Specialist Mathematics scaling to about 36. A strong result in the course with the lower mean beats a weak result in the course with the highest mean among the maths studies. Specialist does pay when the result is respectable: 30 in Specialist scaled to about 43, within a mark of 45 in General Mathematics, which scaled to about 44. The rough break-even on these figures is that Specialist pays off only if a student would land within about 15 study-score points of their General Mathematics result. VTAC publishes these figures as rounded integers and describes them as “an indication” of how scaling adjusts scores, so they are a guide, not an exact conversion.

The ceiling. The highest scaled mark awarded in Mathematics Standard 2 in 2025 was 47.1, and the P99 was 42.9. In English Standard the maximum was 49.3. Scaling reflects how the whole cohort performed, and in these courses even the top result scaled below 50. That is a limit worth knowing, and it cuts both ways. A student at the 90th percentile in Standard 2 scaled to 37.3, below the Mathematics Advanced P75 of 38.9 but well above the Advanced P50 of 33.2 and the P25 of 25.9. For a student who would rank in the bottom half of Advanced, a strong Standard 2 result is usually the better trade.

The check: run your own version of Student A. Pick two candidate subjects, estimate honestly where you would rank in each, and read the scaled marks at those two positions rather than the two means.

Where scaling does count: the top maths courses

The exception is real.

In the 2025 NSW table, a student at the 25th percentile of Mathematics Extension 2 had a scaled mark of 41.5, which is 2.6 marks above a student at the 75th percentile of Mathematics Advanced (38.9). The Extension 1 median was 41.5, and the Extension 2 median of 44.7 sat above the P90 of every course in the table outside the two extensions. In Victoria, Specialist Mathematics had the highest mean of the maths studies at 41.5, and a study score of 40 scaled to about 51, which is where the shorthand that “spesh scales above 50” comes from.

The reason is the cohort. Scaling responds to how well the students in a course perform across all their other courses, and the students who take the top maths courses tend to be strong across the board. UAC’s Table 4.6 shows how concentrated that strength is: among students with an ATAR between 99.00 and 99.95, 67 per cent had an E4, the top band, in Mathematics Extension 2 counting towards their ATAR, and 86 per cent had an E4 in Extension 1.

A vocal minority of students online argue that scaling matters a great deal at the top, and on this point the tables support them. The condition is the one that gets left out of that argument. The gain goes to students who belong in the course, who can keep up with the content and still finish in the middle of a very strong group. A student who is struggling in Extension 2 and would rank near the bottom is the case the “trap” warning describes, and that student usually does better consolidating Extension 1 or Advanced and ranking well there.

The check: ask the maths teacher one direct question, which is where you would be likely to rank in the extension course, not whether you could pass it.

Scaling moves every year

Any published list of high and low scalers describes the cohort that has already sat the exams. VTAC states that “VCE studies are always scaled in the year in which you undertook them”, and UAC recalculates scaling for every HSC cohort in the same way.

The movements are usually small. Between the VTAC 2024 and 2025 reports, a study score of 40 in Specialist Mathematics went from about 52 to about 51, and a 40 in Physics went from about 43 to about 42. Neither change would reverse a sensible choice. They do show that a list consulted in Year 10 describes a group of students two or three years ahead, and nobody outside the admissions centres can know how a future cohort will perform.

The check: whatever list you are shown, look at the year printed on it, then open the current official report and compare.

Myth or strategy: where the advice splits

Two pieces of advice circulate, and they sound opposed. Schools, and the most common view among students online, hold that choosing for scaling is a trap and that a student should take what they enjoy. Tutoring lists rank subjects from best to worst scaling and imply that the order matters. Both are half right.

The ruling, on the 2025 tables: scaling never rescues a weak rank, and it does reward a strong one in a strong cohort. Student A shows the first half, where a top-10-per-cent result in a lower-scaling course beat a middling result in a higher one by 6 marks per unit. The Extension 2 figures show the second half, where even a modest rank in a very strong group scaled above a good rank elsewhere. Students who worry that their subjects “scale down” can take some reassurance from the first half, because a high rank in any course still produces a high scaled mark.

What decides it

UAC’s guidance is plain: “Do not choose courses on the basis of what you believe are the likely effects of scaling.” Choice, it says, should be determined by “your interests, your demonstrated abilities and the value of courses for your future career plans.” VTAC says much the same, warning that “choosing a study that you are not very good at, or engaged in, simply because it may be scaled up would be a mistake.”

That leaves three factors worth weighing side by side. Prerequisites and assumed knowledge come first, because a degree that requires a particular maths or science course will require it whatever that course scaled to last year, and university course pages list these for each degree. Rank comes second, meaning the subjects where a student is likely to finish well up the course, judged on results so far rather than hope. Interest comes third, and it is less soft than it sounds: two years of steady effort is easier in a subject a student wants to do, and that effort is what produces the rank.

What none of the tables can show is how a particular student will develop over Year 11 and 12. That is the limit of any cohort figure, and a reason to weight ability and interest, which a student and their teachers can judge, above a number set by students who have already left school.

The check: open the current scaling report for your state, look up the P50 and P90 for each subject on the shortlist, and set those figures beside the prerequisites for the degrees in view.

What to take into the subject selection meeting

Subject selection is one of the first big decisions a student makes with real numbers attached, and it rewards the same habit in student and parent alike, which is asking the next question rather than accepting the reputation. Three questions cover most of it.

1. Where would I rank in this course? Ask teachers for an honest estimate based on results so far. Rank is the largest single influence on the scaled mark.
2. Which courses are prerequisites or assumed knowledge for the degrees I am considering? These are fixed requirements, and they should be on the list before anything else.
3. If this is a top maths course, do I belong there? If the answer is yes, the 2025 tables show it pays. If the answer is “only just”, the stronger move is usually the course where you would rank well.

A student who chooses on ability, interest and prerequisites is choosing the way UAC and VTAC recommend, and the 2025 figures show why that advice holds. Rank sets the scaled mark, and the top maths courses lift it for students who genuinely belong in them.

Sources: Report on the Scaling of the 2025 NSW Higher School Certificate, Universities Admissions Centre (https://uac.edu.au/assets/documents/scaling-reports/scaling-report-2025-nsw-hsc.pdf); 2025 Scaling Report, Victorian Tertiary Admissions Centre (https://vtac.edu.au/files/pdf/reports/scaling-report-25.pdf); ATAR and scaling guide, Victorian Tertiary Admissions Centre (https://vtac.edu.au/atar-scaling-guide-2025.html)