Empirical Analysis of Regional Inequality in Human Development Index Components Across Nigeria’s Six Geopolitical Zones

Regional inequality in human development outcomes across Nigeria's six geopolitical zones constitutes a critical policy challenge, yet comprehensive empirical decomposition of inequality into within-zone and between-zone components using recent data has not been conducted. This study empirically analyses regional inequality in Human Development Index (HDI) components across all six geopolitical zones using data from the 2022 Nigeria Human Development Report and the 2023 National Bureau of Statistics Living Standards Survey. HDI and its three sub-indices, health, education, and income, were computed for each zone. Theil decomposition separated between-zone and within-zone inequality contributions. Bootstrap confidence intervals quantified estimation uncertainty. Kernel density estimation compared distributional shapes across zones. Mann-Whitney pairwise tests examined inter-zone differences. The overall HDI Theil index was 0.142, with between-zone inequality accounting for 63 percent of total inequality. The North East zone showed the lowest mean HDI (0.41) and the South West the highest (0.64). Education sub-index inequality was the dominant contributor to between-zone HDI disparity. Kernel density plots showed bimodal national HDI distribution, with northern and southern modes, suggesting a persistent structural divide. Between-zone inequality increased between 2019 and 2022, reversing a prior convergence trend. The study provides empirical inequality decomposition evidence and recommends that national development planning prioritise geographically targeted education and health investments in the North East and North West zones. Keywords: regional inequality, human development index, Theil decomposition, geopolitical zones, Nigeria