NSW and Victoria have quietly outperformed the ACT in NAPLAN testing over the past decade, according to a new analysis submitted to an ACT parliamentary inquiry.
While the ACT has long come out on top in state-by-state breakdowns over the test's 10-year history, mathematician Dr Mark Drummond said such comparisons were not scientifically valid, given the overwhelmingly high level of socioeconomic advantage in Canberra.
"Politicians use those comparisons, but they mean nothing, it's masking the real story," he said.
An analysis of results using NAPLAN data broken down into metropolitan areas, which included almost all of the ACT but between just 40 and 80 per cent of other jurisdictions, saw Canberra fall to third on the list, behind NSW and Victoria. When comparing the results of students with university educated parents, the ACT tumbled again in rankings, with a particular slump between 2015 and 2017.
The most stark difference in the figures emerged in writing and numeracy. While above average when compared to state-wide results, the ACT's mean score for writing between 2008 and 2017 fell below the national average in metropolitan areas and further still to come in behind NSW, Victoria, Tasmania and Western Australia under a comparison of students with university educated parents.
In numeracy, ACT student scores also fell from the highest in the country to below average in both metropolitan and parental education comparisons.
Students whose parents have higher incomes and education levels consistently perform better on NAPLAN tests but a number of recent reports have warned Canberra students are lagging behind their peers from similar socioeconomic backgrounds.
For Dr Drummond, the findings raise questions about the territory's decision four decades ago to break away from the NSW education system, now the top performer in the country, according to his analysis.
"Have ACT school children and the community ... benefited or been harmed by [this] ... and moving forward should the ACT return its schools to the NSW system?" Dr Drummond wrote in his submission.
"It has always been difficult for schools in the ACT, with school-based curriculum development ... and management, to match the might of the NSW and Victorian systems, with their formidable structural integrity."
As the ACT government leads the charge on a national review into the controversial NAPLAN testing regime, parents, experts and school associations have shared stories of the assessment's impact in Canberra schools with an ACT inquiry into standardised testing.
In its own submission, the ACT Council of Parents & Citizens Associations also pointed to inconsistencies between schools as the reason for the territory's underperformance in NAPLAN.
With schools running their own show, the council said discrepancies across the sector had created at least the perception of a two-tier education system, leading to strong demand for out-of-area enrolments as parents shopped around for high-performing schools.
The Association of Independent Schools of the ACT echoed such enrolment concerns, but stressed private schools in Canberra did not filter enrolments based on NAPLAN results.
Recent consultation for the ACT government's new future of education strategy had starkly revealed the divide between schools, the parents council said, with some offering a wide range of specialist programs and others struggling to provide a qualified librarian or language teacher.
The council supported tests such as NAPLAN as a crucial tool for identifying student progress and allocating resources, noting many ACT school reporting methods were vague and left parents dissatisfied, including the recent introduction of A to E grading.
But the council's submission also argued such data should be timely, accurate and meaningful, with a focus on student achievement.
In some cases, it said, schools were skewing the data to improve their performance by restricting the participation of a proportion of students.
While parents had told the council this normally happened by "implication" rather than an explicit request, its submission noted such a practice could explain the ACT's relatively high rate of withdrawal from NAPLAN compared with other states.
"Given these students are usually who are struggling – the value of the data is questionable," the submission said, calling on the education directorate to provide greater oversight over test in the future.
The council, along with a number of submissions, also noted strong community concerns about the impact of NAPLAN on student wellbeing and mental health, with the test known to cause unnecessary stess to some though not all students.
A survey of almost 400 students at Canberra's Daramalan College who sat NAPLAN this year found most did not report feeling stressed by the test and supported the new online format.
But the ACT branch of the Australian Education Union slammed NAPLAN as doing more harm than good, a position backed by the majority of the 550 teachers it surveyed ahead of its submission.
The inquiry into standardised testing will sit on Tuesday.