Abstract
An assessment is made of whether primary, secondary or tertiary education has the greatest impact on national income. An aggregate production function is estimated for a cross-section of 77 countries which disaggregates the labour force on the basis of the highest level of schooling attained. The results imply that for both high-income and less developed countries the marginal product of labour increases with each successive level of schooling. Tertiary education has the greatest economic impact.