On the Arbitrariness and Robustness of Multi-Dimensional Poverty Rankings

It is often argued that multi-dimensional measures of well-being and poverty -- such as those based on the capability approach and related views -- are ad hoc. Rankings based on them are not, for this reason, robust to changes in the selection of weights used. In this paper, it is argued that the extent of potential arbitrariness and the range of issues relating to robustness have been underestimated in this context. Several issues relating to both the identification of the poor and the use of dimension- specific data are distinguished. For illustrative purposes, these distinct issues are discussed in the context of the inter-provincial ranking of poverty in South Africa in 1995-1996. It turns out that this ranking is fairly robust, and that an important policy-relevant result involving a comparison between KwaZulu-Natal and the Free State in 'income'/'expenditure' and 'human' poverty rankings is reinforced rather than undermined by checking for robustness. Even when the rankings are not robust, the discussion suggests that they may inform policy debates.