Students who opt for the general mathematics course in the HSC are being rewarded with up to 6.5 marks more than those who study the 2-unit advanced maths course, creating a "loophole" that is pushing high-achieving students into the less challenging subject.
The advantage, created by the Australian Tertiary Admission Rank (ATAR) scaling system, ranged from 5.3 and 6.5 scaled marks or the equivalent of at least 1.3 ATAR points between 2009 and 2013, according to a new report by the NSW Department of Education's Centre for Education Statistics and Evaluation (CESE).
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"The implications are that the scaling is not working as it is intended. Instead of rewarding students who tackle the higher-level course, it is rewarding those who choose the lower level," CESE's executive director Dr Jenny Donovan said.
The ATAR calculation system is at least partially responsible for a steady fall in enrolments in the calculus-based advanced and extension maths courses, according to the CESE report and president of the Mathematical Association of NSW John Meng, who described the trend as "really concerning".
!['We see students who are doing very well in maths deliberately choosing general maths to achieve a band six, which ...](http://web.archive.org./web/20170706201553im_/https://www.fairfaxstatic.com.au/content/dam/images/g/t/7/x/t/7/image.related.articleLeadwide.620x349.gw505a.png/1494848910076.jpg)
"It's become a loophole. We see students who are doing very well in maths deliberately choosing general maths to achieve a band six, which contributes to a very high ATAR score," Mr Meng said.
"Students studying calculus-based courses are reducing, making it challenging to study STEM subjects in universities."
The number of students opting for the HSC general maths course has increased nine per cent between 2001 and 2015, while the proportion of students studying advanced maths has dropped by 10 per cent over the same period, according to the report.
The overall proportion of HSC students studying any level of maths has also dropped significantly from 95 per cent in 1986 to 77.6 per cent of students in 2016, suggesting a broader shift away from maths and a tendency for those still studying it to choose the easiest subject.
In turn, the number of students commencing maths and economics degrees at university has dropped by more than half between 1989 and 2015.
A spokesman for the NSW Education Standards Authority (NESA) said the new maths syllabuses, to be introduced next year for the general maths course and in 2019 for higher-level courses, would address the issue.
"[The new] HSC mathematics syllabuses will feature common content and marking scales that allow direct comparison of students to taking the calculus and non-calculus based courses, and address concerns that ATAR scaling advantages students taking the non-calculus General Mathematics course," the spokesman said.
"NESA will provide UAC with data related to questions which assess common content across adjacent courses for scaling purposes."
However, the success of the common marking scale in addressing the scaling advantage will depend on the degree of common content between the general maths course and the advanced maths syllabus, which has yet to be finalised.
The Mathematics Association has been pushing for changes to the scaling system for years and welcomed the changes, Mr Meng said.
"It's a very good practise that's been in place for standard and advanced English for years," he said.
In the meantime, the University of Sydney has become the first in NSW to set its own prerequisite of a band 4 or higher in advanced maths for entry into 62 courses across a range of disciplines from 2019.
"We have been concerned about falling participation in advanced level mathematics at the HSC level," the university's Deputy Vice-Chancellor Professor Tyrone Carlin said.
"We want to ensure the students we admit to our degrees are adequately prepared for their university studies."
A spokeswoman for the Universities Admissions Centre, which calculates ATARs based on a combination of raw and scaled HSC marks, welcomed the move and said the perception that choosing general maths would help students gain entry to better university courses was "erroneous".
"I know kids are looking to maximise their ATAR and in some cases when they're looking at highly competitive courses, 0.05 points can make a difference, but they're setting themselves up for failure by doing lower-level maths," she said.
"Any advantage is completely swamped by the benefits of university bonus points, which generally reward higher-level maths. And some universities are setting their own prerequisites."
Mr Meng also said university prerequisites were "a good rule".
"Students with higher maths capabilities should do the right course rather than taking a short cut now, because it's building a foundation for tertiary courses," he said.