This note challenges the proposition David Lam made in his attempt to examine the relationship between population growth and the distribution of income. In the first 2 sections of his paper in which no income mobility was allowed Lam successfully analyzed the effects of adding to the economy a group of immigrants (with income distribution different from the original residents) on 2 inequality measures. In the 3rd section Lam made the strong proposition that claims in effect in order to determine whether an increase in the ith-income groups fertility would increase or reduce the steady-state proportion of the ith-income group all the information needed is the ith row of the mobility matrix. A counterexample is presented here along with a correction for the error that is made in the derivation of Lams proposition.

One question development economists are especially interested in but so far left unanswered is: how would the societal income distribution be affected by introducing a family-planning program to reduce the reproduction rate of the poor which is usually high in developing countries? The purpose of this paper is to search for analytical answers to this question. We are able to make definite comparisons about some class of inequality measures of the steady-state societal income distributions and these comparisons provide strong theoretical support in favor of the above-mentioned family-planning program. (EXCERPT)