"We have failed to live up to what we have promised ourselves. It's occurred under both Coalition and Labor federal governments." Between the 2007-08 and 2016-17 financial years, combined state and federal government funding for public schools grew by 22 per cent, adjusted for inflation, while public funding for non-government schools grew by 46 per cent. The disparity is due to a significant increase in Commonwealth money. As the federal government mainly funds private schools and contributes just one fifth of public school funding, more of that money went to the Catholic and independent sectors. The states, which are supposed to cover 80 per cent of the cost of their public schools, have been slower to lift their contributions. When student numbers and teacher wages were taken into account, the states' contribution to public schools was found to have fallen by six per cent, while their payments to private schools grew by two per cent.

Peter Goss is the program director of school education at the Grattan Institute. "The states have been shifting their costs to the Commonwealth," said Dr Goss. "While government schools got more money from the Commonwealth on one hand, they got less from states on the other, and overall didn't see much change." Education economist Adam Rorris, a former consultant to the Schools Resourcing Taskforce, said the present state-federal agreements did not demand the states comply with federally set funding targets. The most effective way to enforce compliance would be to offer the states something in return, such as extra federal money. "That's the only way to stop the drift, otherwise the states will keep pulling money out." While total government contributions to private schools grew over the decade, the number of students from the most disadvantaged quartile in the non-government system fell from 19 per cent to 12 per cent.

"Non-government schools have been getting effective increases in funding, while moving upmarket on average," Dr Goss said. "Government schools have been getting no increase in effective funding while carrying more of the load of teaching more disadvantaged students. "This has to change." Loading Dr Goss said NSW was the only state in which government schools had seen more than half the extra money required under the Schooling Resourcing Standard poured into the system by both levels of government. "Even there, they only got half the extra money, despite educating two thirds of the kids," Dr Goss said. "Victoria was middle of the pack. Non-government schools got three times as much extra effective funding as states schools."

Over the 10 years covered by the data, there was significant reform to school funding in an attempt to make it consistent and fair. The Gonski report was released in 2012. NSW became the first state to sign up to needs-based funding in 2013. In 2017, a formula was established to determine how much money each student should receive. Labor has promised extra money and has pledged to ensure the federal government takes greater responsibility for public school funding if it wins this weekend's election. "Labor's $14 billion to government schools will close a chunk of this gap," Dr Goss said. "Even that won't be fully enough. Labor has to do two things; deliver the money, get its share to 25 per cent and make sure the states put in proper money." If it achieved all those objectives, "government schools would see a real increase over the decade of about $1500 per student, as opposed $150," said Dr Goss.

Loading Federal opposition education spokeswoman Tanya Plibersek said Labor would increase funding, but would expect the states to invest strongly, too. "No excuses, no accounting tricks," she said in reference to a new loophole in which states can count depreciation as a school operating cost. "We held state governments to account last time we were in government, we’d do the same this time, if elected." The Coalition does not plan to change school funding policy if it retains government. However, federal Education Minister Dan Tehan said a re-elected Coalition government would push the states to lift their spending contributions. A spokeswoman for NSW Education Minister Sarah Mitchell said NSW led the country on school funding. "[We] recently have committed an additional $6.5 billion for government schools to ensure that every child has the opportunity for a world class education," she said.