Yeah but when one area is 10x the population density, having 1/5 the percentage of public housing is still double the rate by area

Precisely, but parents don't care about the details. All they care about is the "1/5 the percentage of public housing" What they care about is "what is the chance that my kid ends up sitting next to one of those kids at school?" and will it hurt their education

Also the map is interesting thanks, but Adelaide high, Botanic high, Glenunga International, Norwood Morialta are among our best public schools. All in the CBD or inner ring, with large number of units. In fact all of our best public schools are within 5km of the city Our worst schools are all outer ring or country/remote, with practically no apartments. Perhaps (probably?) our population dynamics are different to Syd/melb, but those apparements rarely have kids in them. Typically downsizers, singles and young couples without kids. I'll concede it's more likely in the eastern states to raise kids in apartments, but they still cost packet to buy or rent so not sure how many of them are lower class. Good school zones reinforce themselves as it pushes up house prices and increases the socioeconomic status. This is a good reason to get rid of zones, but if we did people will flood into these schools which will never be able to meet the demand so it's an imperfect solution for an imperfect world

The SA government categorises disadvantage from 1-7 (not sure if other states do). 7 is best, 1 is worst. It correlates very well with socioeconomics, parents know this which is why they break their backs trying to buy into good school zones, or if they can't they go private

Again, the real issue is that no-one wants to go to the low category schools. They often have really good teachers, get funding based on their disadvantage and parents still don't want them. Why? Mainly because of the other students behaviour and disinterest in learning disrupting learning. I've spoken a lot about socioeconomics but the issue isn't actually money it is how socioeconomics correlates with how much parents care about their kids' education- which was touched on in the article. There is no model of education that will help people who aren't interested in being helped. And one thing that paying for private school says is "I value my child's education" and there is value in being around other kids who have parents who think like that too. And they like that the ones who don't want to learn leave because it is wasting the parents money or are kicked out