Next year, my eldest child will begin kindergarten. Like most ACT parents (63 per cent, to be precise), we've opted for the nearest public school. Yet, by the time Canberra children are ready to start high school, something spurs them to switch from the public to the private system. The ACT has become the only jurisdiction in Australia in which most secondary students attend non-government schools.

To an extent, this is hardly surprising. Canberra is the country's most affluent city; its parents tend to have the disposable income to pay for private schooling. If the rest of Australia enjoyed the wages that we enjoyed, I'm sure a larger number of them would opt for private schools, too.

Yet a recent Australia Institute poll of parents suggested that, while money could buy the privilege of choice, other issues drove our enrolment decisions. It found cost was the main factor for only one in 11 parents when selecting a school for their child. Among those who chose public schools, the top reasons were location (33 per cent) and school values (19 per cent). For private schools, the decisive factors were values and academic achievement (29 per cent each).

However, the institute also asked parents who had children in public schools what they would do if high-quality private education became more affordable. Asked if they would be willing to work longer hours to pay for a switch to a private school, one in three said yes. Asked if they would cut other spending to do so, about half agreed they would.

In other words, don't believe parents when they explain why they selected their child's school: cost is a far greater determinant than most will admit at first blush.

What's behind this response bias? I can only guess that many parents - even when speaking on a phone to a researcher they'll never meet - are too ashamed to say they can't afford the education for their child that they would otherwise prefer. Such is the stigma of identifying as poor (even if it's only ''poor'' compared with the Joneses next door).

As the father of a child about to join a public school community, this saddens me deeply. I want to believe all parents are committed to their children's school, rather than be ever seeking an opportunity to ''escape'' to the private system.

I've written occasionally on education over the past decade and am aware of the very strong feelings of some parents about the divides between public, Catholic and other schools. Many who opt for non-government schools quite rightly resent being seen as wealthy; they make steep sacrifices to give their children what they regard to be the best education. They also point out that, by paying a share of their children's education costs, they reduce the strain on public budgets.

Indeed, one education lobbyist told me last week I was selfish for enrolling my children in a public school because I could afford a non-government alternative.

What a terrible shame the education debate ever came to this, where we feel the need to justify choosing our children's school on the basis of fiscal policy. As last year's Gonski review of school funding made clear, Australian parents have nothing to feel guilty about. Our governments spend appallingly little on education, relative to the size of our economy: 15 per cent less than the average among developed countries. We should be demanding they do far more for all children.

I wouldn't judge any parent on their preference for a school, nor would I expect to be judged. I had a decent Catholic education, which I finished at a selective school. I just want something different for my children: a school they can enjoy walking to, friendships with people near our home, rather than several suburbs away, and a classroom that represents the whole community.

What a tragedy it would be if the meanness of our governments and the parental fear of ''falling behind'' made this simple hope a lost dream.

Markus Mannheim edits The Public Sector Informant.