Julia Gillard threw a lot of taxpayers’ money at the reform to avoid conflict with non-government schools, but couldn’t pull it off. She ended up doing side deals with the Catholic schools and other groups. Malcolm Turnbull’s reworking of Gonski seemed to be more principled, but the Catholic hierarchy kept the pressure up – we want to share the money our way, not your way – and the government buckled. The Catholics got their special deal and the (mainly Protestant) independent schools got something similar to stop them kicking up. Loading What a country we live in. We can happily agree to same-sex marriage, but when Catholics put the frighteners on, politicians on both sides get weak-kneed. Some relevant information has just arrived from Paris. A report from the Organisation for Economic Co-operation and Development has used its PISA worldwide testing of 15-year-olds on maths, reading and science to assess progress on Equity in Education.

Prime ministers love boasting about our economy’s high standing in the world, so how about this: Australia now has the equal-fourth most socially stratified education system among the OECD’s 35 member-countries. Only Mexico, Hungary and Chile can claim to have a more social class-segregated school system than ours. For a country that still likes to think of itself as class-free, that’s quite an achievement.

The report classifies students according to their parents’ socio-economic status, taking account of economic, social and cultural factors. Socio-economically disadvantaged students are those in the bottom 25 per cent of students in their country. Socio-economically advantaged students are those in the top 25 per cent. Similarly, socio-economically disadvantaged schools are those in the bottom 25 per cent of the distribution of schools, based on the average status of their students. If all schools perfectly reflected the socio-economic composition of the total population, each school would have 25 per cent of students in the disadvantaged category, 25 per cent in the advantaged category and the rest in between. Of course, no country’s schools are anything like that lacking in social stratification. In Australia, however, the proportion of disadvantaged students attending disadvantaged schools is not 25 per cent, but double that: 51 per cent. By contrast, the proportion of disadvantaged students attending advantaged schools is not 25 per cent, but 4.6 per cent.

The report also measures the change in the proportion of disadvantaged kids in disadvantaged schools between 2006 and 2015. Loading On average, it fell a fraction, with 22 countries improving and 13 getting worse. Another international distinction for Morrison to boast about: we won silver with a worsening of 5.2 percentage points. Only the Czechs did worse. But why does it matter if our schools become more socio-economically stratified? It matters because, on average, disadvantaged students attending disadvantaged schools don’t do as well as they would if they attended advantaged schools.

Such students face a double disadvantage: one coming from their parents’ circumstances and another from the less conducive learning environment at school. Trevor Cobbold, of Save Our Schools, says information published by the OECD in June shows disadvantaged schools (95 per cent of which happen to be public schools) have more students per teacher, more teacher shortages, more teacher absenteeism and more poorly qualified teachers. It matters because it helps show the price we’re paying for decades of funding schools on the basis of religion rather than need. The Kiwis stopped doing that ages ago, and they have the fourth lowest proportion of disadvantaged students at disadvantaged schools. Save Our Schools president Trevor Cobbold. Credit:Penny Bradfield It matters if you don’t want what we’ve got: a yawning gap between our strongest students and our weakest.

It matters because it has broader implications for society. “Social segregation in schools breeds social intolerance in communities and workplaces and undermines social understanding and cohesion,” Cobbold says. “Schools segregated by class make it more difficult for children to develop a real understanding of people of different backgrounds and to break down barriers of social intolerance.” And then we wonder why politics is getting more polarised. Of course, many factors besides schools are contributing to the growing social stratification of our cities. But schools are something we can influence by adopting better policies. And if you believe in equality of opportunity, the first thing you fix is schooling. As the OECD says, “children from poor families often have just one chance in life, and that is a good school that gives them an opportunity to develop their potential. “Those who miss that boat rarely catch up.”