A fourth ‘I’ of poverty?

Current poverty measurement methodology does not allow a definitive analysis of changes in distribution, through time or between countries, which involve changes in the number or proportion of poor people. By re-opening some of the discussion which has taken place around the incidence, intensity and inequality aspects of poverty, and by revisiting the continuity and transfer axioms, we show that the Bourguignon and Fields poverty index allows considerable ethical flexibility when its parameters are used to full advantage. Significantly, a fourth dimension of poverty, the injustice of it, corresponding closely with Rawls’s concern for the least advantaged, can also be admitted into the picture once the poverty aversion parameter in the Bourguignon and Fields index is fully understood and used appropriately. A novel application leads to a perspective upon the entire class of relative poverty indices which has not been seen before, and also generates both potentially interesting new poverty indices and wider scope for cogent measurement.