First things first – it’s probably not accurate to call them ATAR calculators when they’re not doing so much calculating as they are estimating. I will concede that they are impressive pieces of technology and that in the process of their estimating, a lot of calculating occurs, but students looking towards them as absolute truth is a practice that needs to go.
They use old data
ATAR calculators can figure out exactly what your ATAR is going to be – if you got your scores in the year before. This is because they work with old data, using the marks of students in the previous cohort. This is important because before your marks can be converted to an ATAR, they must first be scaled, and then converted to a percentile. The process of scaling is pretty damn confusing, but the gist of it is that a subject will scale better if their students perform well in other subjects. Since subjects scale differently every year, it’s impossible to calculate how your marks will scale before that information is released later in the year. Instead, ATAR calculators apply the scaling factors of previous years in their estimation.
If you find this whole process confusing, then congratulations – you’re part of the club. Basically, there’s a whole lot of adjusting of marks to ensure each student is compared fairly to get your ATAR, which is a ranking and not a score. This adjusting takes place several times throughout the entire process, and each time depends on data about your specific cohort. Since that information isn’t yet available to the people behind the ATAR calculators, they can only use old data which won’t be totally accurate.
Another huge reasons why ATAR calculators aren’t going to be accurate is simply due to them being used incorrectly. This is because the calculations involved in finding your ATAR use your HSC (or VCE or whatever) marks, which is an average of your exam mark and your moderated school mark. These figures are not known to you until you receive your HSC marks, so it wouldn’t make sense to use an ATAR calculator before then.
Most people will try to use their internal school marks in ATAR calculators, but this won’t give you an accurate estimation. This is because schools assess and mark differently, so a student who receives a 60 in Maths may have been given a much harder test than a student in a different school who scored 70, and in fact their aptitude may be closer to equal than their school marks would suggest.
Therefore, school marks must first be moderated to account for this and ensure that students of different schools can be compared accurately. Again, this moderation factor depends on how your school performs in the actual final exams, so it is impossible to find your moderated score, and thus your HSC mark, until UAC themselves release it to you.
What does this mean for students?
ATAR calculators are most accurate when you punch in your scaled marks – which you only get in December anyway – and even then, the accuracy of the calculation is limited by the old data that they use. Because of this, the figure you get from them should never be treated as a certain fact.
Instead, they should only be used as rough guidelines and always as motivating factors, rather than the opposite. Be wary of complacency that can arise from a high ATAR estimation, because there’s usually still time for you to gloriously stuff up and bring your marks down. Even if you’ve completed all the exams, a high estimate can also unfortunately lead to disappointment if you end up with a lower ATAR than expected.
On the other hand, a low ATAR estimation can easily demotivate you when in reality you had loads of time to salvage good marks, or you were on track to get a higher ATAR anyway. The best thing you can do continue to work hard, play hard, and chill hard – whatever it takes to get through Year 12 happy and healthy.