Maths and science results in Australian schools have been plummeting for more than a decade despite a 70 per cent increase in spending on schools since the turn of the century.

Australia's state and non-government schools now cost a staggering $58 billion a year to run, with the bulk of this coming from state and territory governments. The balance is made up of federal funding, with increases there skewed in favour of non-government schools, and the fees paid by the parents of children at private schools.

Canberrans will derive some satisfaction from the fact ACT schools fared best overall in the PISA results, which saw 14,000 students from 740 Australian schools undergo a comprehensive assessment process last year.

The Australians were just a small cohort of the 600,000 students from 79 different OECD countries who took part.

On the plus side, the ACT recorded an improvement in its results for reading compared to 2015. Less edifying was the confirmation that the territory, like almost every other state or territory apart from Victoria, is experiencing a long-term decline in results in mathematics.

Any serious consideration of the ACT's performance also needs to recognise Canberra has the best educated and most affluent workforce in the country. This is reflected in the fact we have the highest proportion of students in non-government schools in Australia and possibly the world.

The majority of Canberra students would be considered privileged compared to, say, pupils from a drought-stricken bush school in western NSW, one of the outer suburbs of Sydney, Melbourne or Brisbane or from the outback of the Northern Territory or South Australia. Our performance may indeed have more to do with with our circumstances than with education policy.

It is interesting to note that when our results are adjusted to match outcomes from areas of equivalent privilege, Canberra's relative performance begins to fall.

One thing the latest changes in the PISA rankings does make abundantly clear is that it is no longer possible to make a direct link between the amount of money we spend on our schools and the outcomes they deliver. We have gone backwards despite a significant increase in our school spending. Australian schools are also generally faring poorly compared to those in some countries, such as Estonia, that spend half of what we do per pupil.

It is obvious education can't be fixed just by throwing more money at it. Teaching philosophies, curriculum models and methodologies also play a vital role.

That point was made very strongly in the Gonski report; the best, clearest and most precise road map to improving educational outcomes this country has seen in decades.

Countries such as China, which topped this year's PISA ranking, generally have a more rigorous and knowledge-based curriculum than the inquiry-based approach favoured in most Australian schools.

Australia cannot afford to keep getting this wrong. The 21st century will be dominated by countries with highly educated and adaptable workforces.

It is important to note that when the 20th century dawned we had one of the best universal education schemes of any country in the world. We also had some of the highest wages and rates of productivity of any country as well.

That was not just a happy coincidence.