Can the size of a country’s population have a positive impact on the quality of its educational performance? Are children living in small countries more likely to do better than those living in more populous parts? And if they are, what is going on and what lessons can the larger countries learn from them?

Finland is a case in point. A small country of 5.2 million people, it trounced 26 other countries in the Organisation for Economic Co-operation and Development and another four non-OECD countries in the Programme for International Student Assessment study on reading standards of 15-year-olds (see graph). Not only trounced them but had the smallest gap in achievement. And its pupils do not start school until they are seven.

Three of the top five for reading literacy in the Pisa study were also small countries. New Zealand (population 3.9m) came third, and Ireland (population 3.8m) came fifth. The other two in the top five were not population giants either. Canada came second (population 31.1m), and Australia (population 19.5m) came fourth.

Compare that with the United States (population 291m) which only just crept above the OECD average, or Brazil (population 176m) which was the worst performer, or Germany (population 82m) which did surprisingly badly.

You could say these are countries with extremes of wealth and poverty or a higher-than-average proportion of migrant children and they are bound to do less well, but that does not quite hold water. Look at Wales. A small country of only 3m people, it is now doing as well in terms of educational performance and in some cases better than its big neighbour England, despite having more social deprivation, spending proportionately the same and rejecting the rigorous system of testing and league tables that the Government imposes on English schools.

And New Zealand, to take another high-performing example, is not the white Eurocentric, middle-class country of myth. By the year 2020, 40 per cent of its pupils will be non-white because of the high birth-rate among Maori and Pasifika (Pacific island origin) families. There is also a big Asian immigrant population in Auckland and plenty of English as a second language and socio-economic deprivation, particularly among non-white groups.

It is not just the Pisa study in which small countries have done well.

Sweden (population 8.9m) was top of 35 countries in reading for literary purposes in the Progress in International Reading Literacy Study published in 2001 by the International Association for the Evaluation of Educational Achievement (IEA). Finland was not part of that study - participation was voluntary - and neither was Wales, but other small countries shone through.

The top group in performance of reading for information, for example, was Sweden followed by the Netherlands (population 16m) and Bulgaria (8m).

Not all small countries perform well, but Dr Hans Wagemaker, executive director of the IEA, thinks it could be interesting to correlate population size with country ranking in educational performance. He feels that size is probably a surrogate for other factors such as the degree of centralisation that might be possible over the curriculum or teacher preparation.

“Maybe size is important because the larger the country the greater the likelihood that it is more heterogeneous with respect to ethnicity, socio-economic status or social class and language. Diversity along these dimensions poses significant challenges for educational systems,” said Dr Wagemaker.

That said, he recognises that New Zealand is culturally heterogeneous but is scoring very highly on educational performance.

David Reynolds, professor of education at Exeter University, who has noted the correlation between size of population and educational performance, also believes that smallness may be a surrogate for other things such as cultural homogeneity. Or it may be that small countries have small schools - Finland certainly does, a typical comprehensive there has only 300 pupils - and that small schools produce better results.

In Wales, though, where he lives and his children are being educated, there is some acute social deprivation and the comprehensives are not that small.

Here he puts his money on what he calls “connectedness”, which helps good practice travel fast in a small country which also has more of a sense of community than its English neighbour.

Jane Davidson, education minister for Wales, believes that the size of her country is important because it is small enough for her to get round all the schools and listen to the issues that are bothering teachers.

Donald Hirsch, a UK-based consultant for the OECD, will not say with confidence that the small population size per se is the reason for better performance, but he does feel that it might be easier in a small country to make improvements quickly and adapt to changing circumstances. That is harder for a larger country, he says, citing the slow progress that the US is making in improving educational performance despite reforms set in motion during the 1980s. Finland’s success, he believes, is down to efforts to improve the system. “What often happens in smaller countries is that there is a strong cohesive understanding about how to improve things - there is a kind of village mentality.”

Finnish teachers are also highly qualified and competition to train to be a teacher is intense with only 10 per cent getting in and all being trained to masters’ standard.

Smaller countries tend to spend a bigger proportion of their GDP on education, says Mr Hirsch. Sweden, Norway, New Zealand, Austria, Denmark and Finland are all among the biggest spenders. “There is this feeling in small countries that they have to make an extra effort in their education system to preserve their culture. There is a national priority to ensure they are not swamped by an anglophone world.”

Simo Juva, counsellor in the permanent delegation of Finland to the OECD in Paris, confirms this. “In Finland our politicians are taught to think that a small nation cannot waste its human resources because we are so few.

“With a smaller language there are conscious efforts to maintain the national literature, press, film industry and theatre.”

It is interesting that smaller countries are doing so well in literacy surveys; however, the best-performing small countries do well in maths but are not at the very top.

A Pisa report published this week which compared data collected last year from 15 mainly middle-income countries and economies with data collected in 2000, found Japan, Hong Kong and Korea lead in maths and science. Hong Kong also scores well on reading, equalling some of the best OECD countries - but it is still behind Finland, Canada, New Zealand, Australia, and Ireland.

What is clear, says Professor Alan Smithers, Sydney Jones professor of education and director of the centre for education and employment research at Liverpool university, who is currently examining the Pisa study, is that the way a country values education combined with the quality of the teaching force and its stability, are the keys to high educational performance. Both Finland and Wales score on these points. And both of these are in the reach of the largest countries. All it takes is a change of mindset and massive investment in teacher training. Not much to ask really. Size, then, may have its advantages - but it is not just size that matters, but what you do with it.