In the mid 1990s a series of tests were administered to large samples of the adult population in many OECD countries. This was the International Adult Literacy Survey (IALS). Because the tests were identical across all countries, they are a valuable source of information. Surveys such as these are regularly given to schoolchildren, but the IALS has been the only such survey for British adults.
Several features of the IALS results are worth noting. First, the average scores of the top 20 per cent do not differ greatly across most countries. By contrast, the average scores of the bottom 20 per cent differ dramatically.
Second, there is a very high correlation between the dispersion of test scores and the dispersion of earnings in a country—well over 80 per cent. Putting this another way, countries which do a good job of educating individuals at the lower end of the ability range tend to have lower levels of earnings inequality.
It will come as no surprise that Britain has a very high level of test score dispersion to go with its very high level of earnings inequality. In quantitative literacy, 23 per cent of the working age population in Britain were at level one, the lowest level. This compares with 6.6 per cent in Sweden and Germany. The percentage at level one in Britain is much the same in all age groups. So those educated in the secondary modern era and those educated in the comprehensive era reveal the same poor performance.
Recent international tests of 15 year olds carried out under Pisa (Programme of International Student Assessment) seem to indicate some reduction in the level of dispersion in Britain, perhaps because of the recent focus on numeracy and literacy in primary schools. However, there is evidence that weaker students were underrepresented in the sample. We will only know for sure when the next adult literacy survey comes around, which should be fairly soon. But given the fact that, in Britain, the total resources spent on educating the top half of the ability range is vastly greater than that spent on the bottom half, I would not be very optimistic.