What it is
An ATAR Contribution basically answers the question, ‘If I could study just one subject for my HSC and still receive an ATAR, what would my ATAR be?’
HSC scores, by themselves, can't be compared from one subject to another. That's the whole reason we have a scaling system. An ATAR Contribution puts an HSC score in any subject onto the ATAR scale, so scores from different subjects can be read side by side.
How it's worked out
It takes three steps, all using UAC's published figures. Choose a course and a score to follow one through.
- HSC score to scaled mark. UAC scales every course so that marks from different courses can be compared. A scaled mark shows where a student would have placed if every HSC student had taken that course. Scaled marks are shown per unit, out of 50.
- Scaled mark to aggregate. An ATAR is worked out from 10 units, so the scaled mark is counted 10 times, giving an aggregate out of 500.
- Aggregate to ATAR. UAC publishes the lowest aggregate that reached a set of ATARs, from 50 up to 99.95. Between those points, straight lines fill the gaps.
That's why I call every ATAR Contribution an estimate. UAC scales the raw marks behind each HSC score, not the HSC score itself, and publishes the aggregate for only a handful of ATARs. So the first and last steps are close, but not exact. All care is taken to make them as accurate as possible, but treat them as a guide.
Why the same HSC score is worth different amounts
The same HSC score in different subjects will be worth different amounts to student ATARs. For example, an HSC score of 80 in Chemistry is worth about to a student’s ATAR, and an 80 in Visual Arts is worth about . It’s important not to make value judgements based off of this. Chemistry doesn’t scale better than Visual Arts. What is being suggested, though, according to the scaling system, is that an HSC score of 80 in Visual Arts is easier to achieve than an 80 in Chemistry. Scaling gives us some (although not perfect) insight into the academic standards at which the bands are aligned in the HSC marking process. An HSC score of 80 scaling higher in some subjects than others, though, doesn’t give us enough information to make value judgements about which subjects scale well and which subjects scale poorly.
From ATAR Contributions to an ATAR
A student's ATAR comes from their best 2 units of English and their best 8 other units. Roughly, it sits near the average of the ATAR Contributions of the units that count. It isn't exactly that average, because the adding up happens on scaled marks, before the conversion to an ATAR.
So an ATAR Contribution isn't a minimum. If a student scores less than the HSC score that gives a fair contribution to their ATAR Aspiration in one subject, it doesn't prevent them reaching it, but it does create a deficit they need to make up in other subjects. That's what the ATAR Aspiration page shows.
On that page, if every subject is set to the lowest HSC score that contributes positively to the aspiration, the estimated ATAR usually comes out a little higher than the aspiration.
Reading a student's results
The most useful question an ATAR Contribution helps with is, ‘How have students achieved as an ATAR Contribution in my subject compared to their actual ATAR?’
Ascribe value carefully. Just because a student achieved their best or worst result in a subject, there are no automatic value judgements to make. It's important to be willing to see there might be things to improve, and equally important not to bear burdens that aren't yours to bear.
ATAR Contribution and Indicative ATAR
They're the same measure under two names. I coined Indicative ATAR first, and it's the name I use in the HSC reports I prepare for schools. ATAR Contribution is the name I use in everything public, including this site, because most people find it more intuitive.
If your school's reports show an Indicative ATAR for a student in a subject, read it exactly as you would an ATAR Contribution.
Worth keeping in mind
- They describe last year. Every figure comes from the HSC. Scaling shifts a little each year with the students who take each course, so this year's will differ.
- They're cut, never rounded up. ATAR Contributions show one decimal place with the rest cut off, and anything at or above the top of the scale shows as 99.95+.
- Some courses are estimated. When too few students take a language for UAC to publish its scaling, its figures are estimated from French Continuers (or French Extension for Extension courses). Those courses say so on every page and download.
- Extension courses have their own scale. Mathematics Extension 1 and 2 are out of 100. All other Extension courses are out of 50, with bands E1 to E4.
- Low scores aren't published. Numbers of students on each score are only published from Band 2 (or E2) up.