Professors Connors and McMorrow said the extra 634,068 students that were educated in private schools in 2012 could have been educated in government schools for $7.42 billion in 2012 as opposed to the $9.47 billion spent by the state and federal governments on independent schools in that year. Authors Lyndsay Connors and Jim McMorrow The research, funded by the Australian Council for Educational Research, a not-for-profit organisation that administers the medicine university entry exams and other tests, found that independent schools had a disproportionately high expenditure on capital facilities, grounds and buildings. It also found the relatively wealthier intake of students into the non-government sector had the effect of leaving government schools with an increasing share of students with higher needs and extra costs. The findings are at odds with the Productivity Commission's 2015 Report on Government Services, which showed that average government expenditure in 2012-13 was $15,703 a student in a government school and $8812 a student in a non-government school, a saving to the taxpayer of almost $7000 a student, or $8.6 billion annually.

The Productivity Commission's report takes into account the cost of capital, including the value of buildings owned by private and public schools. ACER has based its figures on the amount of annual income received by each school according to the MySchool website. The executive director of the Association of Independent schools NSW, Geoff Newcombe, described the research as flawed for its selective use of data. "In attacking the right of parents to choose a school and to receive government support for their children's education, the report simply underlines a divisive ideology that contributes nothing to education," Dr Newcombe said. "How parents use their after-tax dollars is entirely a private matter and it's hard to argue that spending it on education is a bad thing." The research found that in up to 95 per cent of all Australian schools teachers' salaries are covered by public funds, with the exception being the top tier of private schools. Out of the $10 billion allocated by state and federal governments, $8 billion was spent on teachers in 2011. Dr Newcombe said that conclusion was simplistic because it disregarded the many other areas of expenditure for schools, such as facilities, which attracted families to private schools.

"As the first state to sign up to the Gonski agreement, NSW is leading the way when it comes to advocating for funding to be based on the needs of students regardless of whether their school is in the public, independent or Catholic sector," he said. "We remain committed to funding our share of the six-year Gonski agreement and continue to advocate for the federal government to honour the agreement in full."