A Decomposition of the Sen Index of Poverty Using the Analysis of Gini

This paper provides a decomposition of the Sen index by subgroups using the analysis of Gini. This method decomposes the Sen index, isolating the contribution of the poverty gap, those of within and between inequality, as well as the contribution of overlapping. The application of this method to the analysis of world poverty in two years shows that the evolution of the Sen index and of all its components can be easily captured and interpreted, a feature that significantly improves the use of the Sen index in poverty analysis.