Teaching Matters: Class size in primary schools has become a hot potato in recent weeks. It all started when the Minister declared that the government's promise to reduce class size for children under nine to less than 20 was a "noble aspiration". Predictably, INTO general secretary, John Carr, hit the roof and in less than 24 hours the Minister was back in the media stating that she was committed to reducing it, but that it would take time, writes Valerie Monaghan

Normally that is a euphemism for inaction but this time it might be different. We are only two-and-a-half years from an election when this will become a real issue on the doorsteps. It won't be a minority issue either. It is hard to believe that there are over 110,000 children in classes of between 30 and 39 pupils. Another quarter of a million are in classes of between 20 and 29. That is simply too many votes to ignore.

Another reason why it will be different this time is that there'll be plenty of teachers. Every year about 800 teachers are needed to replace those who retire or change jobs. In 2005, there will be about 1,000 teachers coming out of college over and above this replacement figure. It will be the same the following year and the same the year after. That's 2007 - the election year.

So if nothing is done to reduce class size there could be anything up to 3,000 teachers on the dole! Imagine their anger, and the anger of their families, if their talent, effort and commitment is not utilised by government.

And there's one more reason why I think it will be done this time. Parents all over the country are beginning to get angry about the size of the classes in which their children learn. It's written on the faces of many parents as they bring their four-year-olds to school and find that they are in classes of 30, sometimes more. These children have come from crèches where there's one adult to every eight children.

It's at this age that class size matters most when children are starting to learn to read, write and count for the first time. Most children at this age need some individual attention. If there are 30 children in a class then the simple mathematics are that each child can get a maximum of eight minutes of the teacher's time. But that's assuming that no time is spent organising lunch, buttoning coats or administering first aid after a fall in the playground. So in reality there's nowhere near eight minutes available. Just where is the teacher supposed to magic up the time to hear each child's reading? Government likes to pretend that things are much better than they really are. Spokespersons for the Department of Education never miss a chance to try and confuse the issue and convince the public that things are not that bad. To do this class size figures are ignored and the lower pupil teacher ratio figure is trotted out.

This is spin - plain and simple. Pupil teacher ratio and class size are as different as chalk and cheese.

To get pupil teacher ratio the total number of children in schools is divided by the total number of teachers. This includes principals, some of whom don't teach class, and learning support and resource teachers who help children with special needs. These teachers do a vital job but they don't teach classes. Therefore counting them in the argument about class size is misleading.

Yes government has increased the number of resource teachers in the system and is entitled to highlight this. But it is not entitled to pretend that pupil teacher ratio bears any resemblance to the reality of class size.

I met a colleague the other day who complained that she had 36 children in Fifth Class. She explained that while her class was huge some classes in the junior section of the school were small. When, she complained, would the Department realise that we cannot plan the births of children neatly to ensure that ideal class size numbers arrive at the doors of our schools each year? The Department would like to mix and match every class in the school to keep down class size numbers. Imagine the chaos if a parent enrolling a four-year-old was told that junior infants was full but "there's spare capacity in fifth class with the 11-year-olds."

One thing that is scaring the life out of the Department of Finance is the cost of extra classrooms to accommodate new teachers. Last week I came across a potential solution when I visited a school in the North. I was green with envy. The facilities were just fabulous - computer suites (plural), science room, lunch room, music room, library, conference rooms, a suite of offices and a PE hall. The classrooms were superbly equipped.

I was stunned when the principal told me that they are getting a new purpose-built school and hope to improve the conditions for the future. I told her that a lot of my colleagues would be happy to send up a lorry and transport her school to replace some of the shacks that pass for school buildings down here. After all, in the world of cars, Japanese imports wasn't as daft an idea as it once seemed.

However the problem of large class sizes will be solved, I would remind government that the clock is ticking. "If you don't invest properly in our young people now, you'll never get the chance again."

Valerie Monaghan is principal at Scoil Chiaráin, Glasnevin, Dublin