Teaching Matters: The large class sizes in our primary schools featured strongly in media coverage of "back to school" this month. In between the pictures of happy children starting school for the first time and their sometimes tearful parents were many reports of classes with more than 30 pupils.

There were also tales of children being turned away from schools because of a lack of spaces, showing even greater levels of overcrowding.

In general, these reports centred on urban areas where large housing estates have sprung up with the speed of an Olympic sprinter, leaving the school building programme trotting along like a tortoise in their wake. But these reports showed only one aspect of the extent and the scale of the problem.

One could be forgiven for thinking that overcrowded classrooms are an urban problem only, and that there is a class size utopia to be found in smaller, rural schools. Nothing could be further from the truth.

Many smaller, rural schools also have large classes, where the challenges of teaching and learning are even greater because of mixed classes with two, three or sometimes even four classes in the one classroom.

The tale of one such school shows how class size in small schools is a major challenge to policy makers.

A friend of mine works in a rural school that a year ago had 80 pupils and three teachers. The school was delighted when, at budget time last year, the Minister for Education and Science, Mary Hanafin, announced extra teachers to bring down class size. They thought, even with a minimum reduction of one pupil per class, that this September the school would have been able to employ a fourth teacher.

There was plenty of room for optimism listening to Hanafin. She told every available audience that from this school year there would be 28 children per classroom teacher, down one from 29. What she didn't tell schools was that this reduction of one per class would not apply to small schools. It was in the small print that small schools would only get a reduction of one for the whole school, not per class in the school.

And so in this particular school, the harsh discovery was made that there were to be no reductions in class size. That was bad enough, but just when you think things couldn't get any worse, they did.

Last June, five pupils left the school but 18 new pupils were enrolled. This brought the total enrolment to 93 pupils for this school year, well in excess of what is needed for a fourth teacher to be employed. But despite the fact that all 93 children are in the school, the Department of Education and Science rules state that another teacher may not be employed until September 2007, 12 months from now. The school must carry on for a full year with 31 pupils for each teacher.

To rub salt into already raw wounds, Hanafin recently blamed schools for large class sizes. She told the parents of the nation that anyone who had a problem with the size of the classes was to go to the school for an explanation because it wasn't her fault. She was providing a teacher for every 28 children.

The parents in my friend's school firmly know that in their case the fault lies squarely with the Department of Education and Science and not the school. They were also among the 200,000 parents who signed petitions calling for smaller classes. They hardly expected that almost immediately their children's classes would get bigger.

The rule that states that teacher appointments to schools are based on enrolment figures that are a year out of date belongs to an Ireland that has long gone. It must be looked at again in the context of pupil enrolments that are more volatile because of changed employment trends and practices. This rule must be changed to allow schools to employ enough teachers to meet their pupils' needs in any given year, not the following year. The present system is like promising an umbrella tomorrow when it's raining today.

There must also be a radical examination of the schedule by which teachers are appointed to small schools. At the moment, a school of 50 pupils can appoint three teachers while a school of 80 pupils can have a fourth, albeit after a year-long wait. And while waiting for the fourth teacher a school can, like my friend above, have 93 pupils. This schedule itself contributes to large class sizes.

Small rural schools make a valuable contribution to the fabric of our society. They are the lifeblood of many communities and in some cases all that is left now that garda stations and post offices have been closed. Our children are more than statistics, and archaic rules and unfair schedules that penalise small schools must be changed.

In the end it comes down to mathematics. The Minister should realise that 93 pupils divided among three teachers is 31 pupils in a class, not 28. But then, as every student knows, it helps when you understand the question!

Valerie Monaghan is principal of Scoil Chiarán, Glasnevin, Dublin