The present paper, starting from evidence of low growth-to-poverty elasticity characterising Africa, purports to identify the distributional changes that limited the pro-poor impact of the last two decades’ growth. Distributional changes that went undetected by standard inequality measures were not showing a clear pattern of inequality on the continent. By applying a new decomposition technique based on a non-parametric method—the ‘relative distribution’—we found a clear distributional pattern affecting almost all analysed countries. Nineteen out twenty four countries experienced a significant increase in polarisation, particularly in the lower tail of the distribution, and this distributional change lowered the pro-poor impact of growth substantially. Without this unfavourable redistribution, poverty could have decreased in these countries by an additional five percentage points.

The resurgence of economic growth over the last two decades in sub-Saharan Africa has recently come under scrutiny by scholars, the main criticism being the lack of inclusiveness. While studies on inequality in sub-Saharan Africa are becoming numerous, less attention has been devoted so far to the growing polarization the region is undergoing. Polarization, as distinct from inequality, refers to the tendency of shifting away from the centre of a distribution to its tails, creating a hollowed-out middle. This paper, using a set of sub-Saharan African national household surveys, provides a first estimate of the regional expenditures’ polarization. This latter steadily increased throughout the 2000s and its growth was mainly driven by increasing polarization between countries, meaning sub-Saharan Africa tended to polarize spatially, with the Southern cone countries and some Western African countries performing above the average, and the rest of the region lagging behind.

The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.

The development path of Sub-Saharan Africa (SSA) over the past two decades has been characterized by sluggish poverty reduction occurring alongside robust economic growth. Applying polarization measures to comparable survey data from 24 SSA countries, we find that there has been a generalizable increase in polarization over the past two decades—and in particular, an increased concentration of households in the lower tail of the welfare distribution of SSA countries. The polarization process is further analyzed by identifying the main drivers and singling out the effect of different covariates at different points in the consumption distribution. This investigation reveals that the drivers of polarization are relatively similar across SSA: demographic, urban/rural, regional variables and access to basic infrastructure are found to be the most important drivers of polarization in many countries.

The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.