COUPLE of scenarios: 20 teenagers, working safely with boiling water, ovens and kitchen knives, all subject to the temper swings of adolescents, one or two perhaps with a history of violence; 30 six-year-olds developing their writing skills, with very different maturity and language levels, speaking several different languages, some disadvantaged by poverty.

The feature common to both scenarios is the presence of a teacher; another common feature is that everyone takes it for granted that teachers carry out their responsibilities highly successfully.

For years, it was argued that class size did not matter. This position is no longer tenable, first because there is now strong evidence that attainment is affected by class size; and second because we have to look at the impact of class size on indicators beyond narrow measures of attainment. The benchmark study remains the Tennessee Star programme which demonstrated incontrovertibly that small class sizes in the early years led to significant long-term improvements in attainment.

It could be argued (indeed was argued immediately by those concerned at the implications) that the lessons of this study may not be transferable.

However, other US states have adopted similar practices and there is growing evidence of the positive effects of small class sizes in other continents. London University has carried out a longitudinal study in England, the results of which are summarised in the 2002 publication from the Scottish Council for Research in Education, Does Small Really Make a Difference?

“The findings accord with American evidence . . . the message is clear: an association was found between class size and pupils’ attainment on standardised tests. Test scores for literacy decreased as class size increased . . . and again low achievers show the largest effects from being taught in small classes.”

An analysis based on all children born in England and Wales in one week of 1958 has concluded that class size has a substantial effect on the decision to stay on at school and therefore on final attainment. The results of the Pisa programme developed by the Organisation for Economic Co-operation and Development (OECD) demonstrate that attainment correlates with student-teacher ratios, a rough surrogate for class size. Evidence within Scotland is limited and not statistically reliable but tends to point in the same direction.

Large class sizes are not merely associated with lower attainment: they impact on pupil behaviour, on pupil motivation, on pupil self-image. These qualities are difficult to foster when the teacher must spend most of her time managing a large group. As the SCRE report notes: “Most studies show that teachers of smaller classes report that these are quieter and more easily managed than larger ones. Therefore, potential discipline problems are prevented from arising.”

This is supported by the conclusion that “American researchers . . . claim that fewer of those pupils who experienced smaller classes in the early years of schooling subsequently dropped out of school at grade 10 . . .

Their exclusion and absence rates are also lower. There is some European evidence to link larger class and school sizes with increases in the number of incidents of pupil pushing, crowding and other aggressive behaviour.”

The views of teachers, parents and pupils expressed through the national education debate were clear: reasonable sized classes are a precondition if pupils are to thrive and flourish.

It is argued that we cannot confidently state that reducing class sizes is the best (usually interpreted as “most cost effective”) means of improving education. Ewan Aitken (TESS, April 11) argued that pedagogy, class organisation and the use of ICT may be the keys . No one would disagree that these are crucial factors but most would agree that these are dependent on class size. Indeed Mr Aitken himself, despite his general criticism of the need for reductions in class size, acknowledges this:

“Smaller classes do make a difference but not as an end in themselves.”

he recent survey by the Educational Institute of Scotland of provision for vulnerable pupils resulted in many respondents referring to the impact of large class sizes on their ability to meet the needs of challenging pupils.

The success of nurture groups (belatedly recognised by Glasgow City Council) has been dependent on the relationships built up among pupils and staff, which would have been impossible in a larger class.

With an average class size of 25.5, Scotland now has larger classes than most OECD countries, where the average is 22. The present maxima were, for the most part, set in the 1970s and reflect the ways in which schools worked and subjects were taught in that period. Classes at or near the maxima constrain teachers’ creativity and limit pupils’ learning.

The recent election is the first in Scotland in which most parties fought campaigns that recognised the validity of the argument for smaller classes and promised to reduce class sizes. The EIS will continue to press for these promises to become reality to ensure that the needs of individual pupils are addressed.

If we are serious about promoting better learning, we now have to consider how best to organise classes to meet individual needs and how to develop the skills teachers need to work effectively with smaller classes. But the most urgent task is work-ing out where the priorities are in cutting class size.

George MacBride is education convener of the Educational Institute of Scotland.