Applications of control theory to economic analysis: J.D. Pitchford and S.J. Turnovsky,Editors, Amsterdam: North-Holland, 1977, 364 pages,Dfl. 155.00

A.K. Sen's index, P, is the only measure of poverty in a population that adequately allows for numbers in poverty, intensity of average poverty, and income distribution among the poor, while respecting two natural axioms. Nevertheless, the derivatives of P possess at least four attributes, at best highly counter-intuitive, at worst inconsistent with diminishing-marginal-utility assumptions, underlying the axioms themselves. Due to problems in handling income distribution among the poor, no measure of aggregate poverty can be constructed. Instead, it is proposed to construct a simple measure of those in ultra-poverty - among whom income cannot be very unequal - plus a pair of measures of moderate poverty.