the important of the law zero correlation for development, and in particular for understanding the tensions brought about by educational expansion, is that it points to the source of some of these tensions. In effect as levels of school attainment rise, the social values accruing to attainment will decline. Thus as participation rates at any level, foe example secondary school, increase, the aggregate social benefits to those reaching that level will decrease. When 100 percent of a population or relevant subgroup have a secondary education, then that level loses its advantage. However, on the other side of the coin, if almost the entirety of a population increasingly attains certain levels, then for those who have not done so there is increasing liability.