Data analysis by the Australian National University (ANU) shows ACT school students are several months, sometimes years, behind their peers in writing and numeracy.
Researchers from the ANU School of Law studied NAPLAN results from 2012-2016 for ACT schools and compared it to the same data for equivalent schools in the same socio-economic profile.
Lead author Professor Andrew Macintosh said the results were alarming.
"The analysis showed ACT schools - both government and non-government - are being outperformed by comparable schools in other jurisdictions in writing and numeracy across all age brackets," Professor Macintosh said.
"This research demonstrates, once again, that learning outcomes are not solely linked to resourcing. The ACT has some of the best resourced schools in the country but their students are still underperforming."
The research showed more than 75 per cent of ACT government schools had more than 66 per cent of their results below the equivalent results of statistically similar schools. The results were similar for ACT non-government schools, with 70 per cent having 66 per cent or more of their average results below those of their equivalent schools around the country.
Professor Macintosh and Debra Wilkinson said the ACT Government should lead the way in trialling alternative teaching methods to improve student outcomes, and in demonstrating how NAPLAN data can be used more effectively to inform decision-making by policymakers and schools.
"At the 2016 election, the ACT Labor Government promised to undertake a trial of teacher-led approaches in ACT schools. It is time for that trial to get underway, and for the Government to take this opportunity to engage with the government and non-government school sectors to demonstrate how NAPLAN can be used more effectively to improve outcomes."
The research paper, Academic underperformance in ACT schools: An analysis of ACT school performance in NAPLAN over the period 2012-2016, is available on the ANU website.