Public schools are no longer accepting students who live outside the area. Photo: Michele Mossop
Public schools in northern Sydney are bucking a trend. They are so full the state government has made a commitment to open two new schools and extend five. In the meantime, public school playgrounds are disappearing under the weight of portable classrooms.
Public schools are no longer accepting students who live outside the area.
No one is entirely sure of the reasons. There has probably been a rise in the number of school-age children in north Sydney, but it may also be due to what NAPLAN and other evidence says: it is not a school's ownership that makes the difference, it is the socioeconomic status of the pupils.
Savvy middle-class parents know local public schools are getting just as good results as nearby private schools, and they are wisely hanging on to their money.
Word is that some of these private schools are finding it harder to maintain their enrolments and are recruiting from out of the area.
The most desirable children from less prosperous areas are being bussed in, joining those who have long trekked across town (at public cost) to whatever elite private or selective school they can access.
You will have noticed the effects of this wholesale movement of children across town by train, bus or family car if you commute in any capital city.
Parents who have a choice increasingly want their children to attend schools that are higher up the social ladder. The trouble is, moving students around to different schools is, in the end, a zero-sum game. It may be fine for children whose parents can afford to pay fees, but what does it do to those left behind?
The daily commute of students who have some kind of transactional value - a family that can afford fees, or a child with a special academic, sporting or musical ability - is rapidly residualising the lower socioeconomic schools.
This is what happens when you make schools into a market - you create winners and losers. The tragedy is that the ''losing'' schools are struggling with children whom society has decided are losers.
Just as MySchool demonstrates the public school boom on the north shore, so too it shows how location and socioeconomic status are affecting the achievements of schools and students everywhere.
The website tells us more about schools' socioeconomic statuses; we also have other measures of students' achievements at the end of year 12 - for example, the HSC in NSW and the VCE in Victoria.
Combine this information and the picture becomes scary.
If we group the 400 or so Victorian schools with year 12 students into four socioeconomic groups, the spread of VCE scores tells us what we might already know: students in the schools in the top socioeconomic status group still achieve consistently high results, and the distribution of high VCE scores falls off as we move down the socioeconomic scale.
However, the gap is widening. In only eight years, the share of high scores in the lower socioeconomic status schools has dropped - by more than 20 per cent in the lowest socioeconomic status schools.
With few exceptions, this trend defies the usual explanations. Is it just Victoria? Unlikely; limited NSW data shows similar trends.
Is it just public schools? No. Is it due to enrolment shift?
We are almost certainly witnessing an inevitable result of the hollowing out of low socioeconomic status schools - and the exact opposite to what is happening in north shore public schools.
Almost 60 per cent of disadvantaged students attend equally disadvantaged schools. We appear to be creating ghettos of privilege and underprivilege. Strugglers sit next to strugglers in some schools and the fortunate next to the fortunate in others.
When you group disadvantaged children in the same schools, it compounds their disadvantage. No surprise, then, that it is becoming harder and harder to improve the achievements of our lowest achieving students.
We know all this; the Gonski review laid it bare and helped raise concerns.
So, with an election looming, what chance do we have to fix this problem? If we go by the main political parties' track records - rather than their election promises - the choice is dismal but clear enough.
Labor's plan for schools - often parodied as ''Gonski-lite'' - might begin to close the gap.
The Coalition does not even get the problem; in its hands we will not have any solution.
Jane Caro and Chris Bonnor are co-authors of a chapter on school education in Pushing Our Luck, to be published by the Centre for Policy Development.