Preliminary Naplan results for 2016 show national writing, reading and numeracy scores have plateaued since 2013, prompting the federal education minister, Simon Birmingham, to call for a focus on evidence-based teaching rather than funding.

“Today’s results show that, despite significant funding growth, we are not getting sufficient improvements in student outcomes,” Birmingham said.

“This Naplan data clearly shows that while strong levels of investment in schools are important, it’s more important to ensure that funding is being used on initiatives proven to boost student results.”

The data released on Wednesday reveals minor national increases in reading and numeracy scores of 0.4% and 1.3% respectively across all year levels. Writing scores dropped slightly, by 0.2%.

Meanwhile, federal school funding had increased by 23% in the same three-year period, Birmingham said. The results meant more needed to be done to ensure funding allocated to schools was being used effectively, he said, and that teacher training was improved.

His comments follow those made in April by the prime minister, Malcolm Turnbull, before the election that no extra Gonski money would be allocated to schools, citing controversial evidence that funding increases had not improved educational outcomes.



“Of course investment in our schools is important, which is why we will continue to grow funding from a record $16bn this year to $20.1bn in 2020, all to be allocated based on need,” Birmingham said on Wednesday.



“Our funding growth is sustainable but will be tied to a range of evidence-based initiatives to support students by focusing on outcomes in literacy, numeracy and Stem [science, technology, engineering and mathematics] subjects, helping lift teacher quality and better preparing our children for life after school.”

But education experts said looking at national Naplan data did not provide an accurate picture of the impact of funding on the performance of schools. The schools education program director at the Grattan Institute, Peter Goss, said more comprehensive, long-term data was needed.

“The only real way to do a high-level analysis on the impact of funding on performance is to look at schools that have had a boost in funding over time and see whether that has boosted their results when spent well, or to compare schools from similar backgrounds but with different levels of funding and to see whether those that are better-funded are doing better in comparison,” he said.

“Those analyses are both worth doing, but neither approach has really been done. However, international evidence is that for disadvantaged schools, increased funding can make a real difference just on its own.”

While overall national, state and territory figures were released on Wednesday, the results for individual schools will not be released on the government’s MySchool website until next year.

A former principal and fellow of the Centre for Policy Development, Chris Bonnor, said with Gonski funding only rolled out from 2014, it was still too early to ascertain the impact the funding was having on the schools the money was supposed to target; under-performing and under-resourced ones.

“Next year’s MySchool data will be the first chance we genuinely get to see if needs-based funding in some places is starting to lift results,” Bonnor said.

“Whether the Naplan results reflect on whether funding is the answer is too early to say. But making any claim that extra funding has not changed results because results have levelled-out is a nonsense.

“A range of factors may have led to a plateau in results, and we know from the experiences of other countries that if you implement a new barrage of tests like Naplan, results get better for the first few years as teachers get better at teaching to the test and then of course level out.”

He said the greater issue not reflected in the results released on Wednesday was the growing gap between schools enrolling advantaged students and those enrolling disadvantaged ones.

“It’s not a dramatic widening gap, but it’s a consistent one, and this is the story nobody tells because they don’t want to hear it, but it has damaging effects,” Bonnor said.

“Until we lift struggling kids in struggling schools, we won’t pick up the country.”

NSW has been named a standout state by experts including Bonnor for allocating Gonski funding on a needs basis and directing money to the most disadvantaged schools.

The state’s education minister, Adrian Piccoli, said while NSW was heading in the right direction, evidenced by a greater number of students placing in the top two Naplan bands, the Gonski needs-based funding model and the extra dollars were only part of the picture.

“Evidence-based reforms cost money to implement and take time to take effect, especially in schools servicing disadvantaged students,” he said.

In May, the Coalition outlined a range of reforms as part of its student achievement plan to improve academic performance, including boosting the number of teachers specialising in literacy and numeracy, annual reports to parents that compare their child’s results to national standards, and minimum standards of literacy and numeracy skills for year 12 school leavers.