If there were extra funds to spend, should they be spent on early childhood interventions or secondary education?
Different estimates of returns were identified which are useful in looking at the value of early childhood interventions and secondary education but are not directly comparable. It is difficult to draw conclusions from the different data reported due to difference in methodologies, timelines and countries. In some reports there are different data for social and private returns. There may also be differences in the interpretation of cost-effectiveness data and rates of return.
Research in the US suggests that human capital investment decreases as a child grows older. However, looking at the data on schooling the returns from primary, secondary and tertiary in developing countries do not often diminish but in many cases increase.