the marginal social benefit of additional years of schooling rises more slowly, and the social returns curve begins to level off. By contrast, the social cost curve shows a slow rate of growth for early years of schooling (basic education) and then a much more rapid growth for high levels of education. This rapid in crease in the marginal social costs of post primary education is the result both of the much more expensive capital and recurrent costs of higher education education (buildings and equipment) and the fact that much postprimary subsidized 39 countries is heavily developing