Australian National University paper The characteristics and potential effects of the schools that Indigenous Australians attend concluded that the school a student attends matters in improving their scores in the standardised test.

Authors Nicholas Biddle and Ben Edwards found the state or territory in which a student attended school appeared more likely to impact on their growth in literacy or numeracy above whether their school was public or private, or regional or remote.

The ACT, New South Wales and the Northern Territory were described by Associate Professor Biddle and Associate Professor Edwards as "not doing as well" as other states, with each recording the lowest growth through time in literacy and numeracy. The measure refers to an improvement in results from test to test.

While ACT students started well, they didn't improve at the same rate as those in other states, Associate Professor Biddle said.

"When we look at the data and we look over time we actually find that ACT students don't improve as much as other students do, even holding constant where they were at the start and their other background characteristics," he said.

"You would expect that students would continue to grow through time but the data doesn't really support that that is currently occurring."

A report into Aboriginal and Torres Strait Islander outcomes in Canberra schools released by the ACT government in September showed Indigenous students were two to three years behind their peers in NAPLAN.

Associate Professor Biddle said it was difficult to pinpoint why Indigenous students living in the ACT were not recording the growth seen elsewhere.

He noted Canberra's Indigenous student cohort was quite small and relatively mobile, suggesting children may attend school in other states between tests, though noted the study looked at long-term data.

"Certainly there is variation through time but when we pull and combine the cohorts across a number of years we still find similar effects. It's not like this was a one-off due to a random cohort not doing particularly well," he said.

"The ACT government needs, in my view, to have a look at the extent to which not only are the school students in the ACT starting off relatively highly, which they do, but that there's support for continuous growth in literacy and numeracy across the primary and secondary years and the extent to which they could trial and invest in ways to improve literacy and numeracy across the distribution of existing skills."

Education Minister Yvette Berry said the Education Directorate was working to improve connections with Aboriginal and Torres Strait Islander families, hire more Indigenous teachers and encouraging schools to develop Reconciliation Plans.

"There's no doubt the ACT can do better for Aboriginal and Torres Strait Islander children and this report contributes further evidence for the government's clear direction of improving equity across the school education system under the Future of Education process," she said.

"This priority is also being addressed through key initiatives such as the Student Resource Allocation program (needs based funding) and work to strengthen cultural integrity in schools as a key factor in student success."