Research in developing countries indicate that the incidence of child labor actually rose in some countries as incomes (and wages) of poor families increased. This is difficult to understand since many people assume that as incomes rose, the incidence of child labor should fall since as families become wealthier, school enrollment among children should rise.

Assuming that the alternative to working, children would attend school, carefully explain the paragraph above with the help of a graph using indifference curves, budget lines and the concepts of income and substitution effects. Be clear in your answer about the assumption (or assumptions) that are needed to arrive at the conclusion.