In attempting to raise levels of educational achievement and attainment, countries will obtain the greatest increase in overall national performance if they raise the performance of the lowest achievers and of those with the lowest level of qualifications. These are the groups whose improvement will make the greatest difference to the national average. Policies that specifically target low achievers and those with few formal qualifications have a special relevance to two groups outside the education system: youth who have dropped out of school without having completed a secondary education qualification, and low-skilled adults. The pressures for public policy to focus on these groups come from many sources. Equity, both within and between nations, is a powerful motive. But there are also strong economic pressures to raise the educational performance of low-skilled adults and out-of-school youth. In OECD countries with ageing populations, the prospect of a shrinking labour force leads policy makers to seek ways to increase the supply of labour, and to improve overall educational performance through raising the skills of the existing workforce. These pressures intensify as countries seek to compete in the global economy on the basis of the quality of their human capital.