Statistical Assessment of Internal Revenue Generation Performance in South South State Governments

Internally generated revenue (IGR) performance across South South state governments reflects fiscal autonomy, governance capacity, and economic diversification beyond oil revenue dependency, and its statistical assessment enables benchmarking and performance attribution analysis. This study statistically assesses IGR performance across the six South South states (Rivers, Delta, Bayelsa, Akwa Ibom, Cross River, and Edo) from 2018 to 2022 using data from the Joint Tax Board and state revenue service annual reports. IGR per capita, IGR-to-FAAC receipt ratio, and annual IGR growth rate were computed for each state and year. Panel data analysis using fixed effects regression identified determinants of IGR performance, including non-oil GDP share, urbanisation rate, and number of registered taxpayers. Wilcoxon signed-rank tests compared pre-COVID and post-COVID IGR levels. Rivers State consistently recorded the highest IGR per capita (mean N38,400 per annum), while Bayelsa recorded the lowest (mean N8,200). Panel fixed effects regression showed that non-oil GDP share (coefficient 0.44, p = 0.003) and taxpayer registration rate (coefficient 0.37, p = 0.008) were the strongest determinants of IGR performance. A statistically significant post-COVID IGR recovery was confirmed by 2021 (p = 0.032 by Wilcoxon test). The study provides a comparative fiscal performance statistical assessment for South South states and recommends taxpayer identification expansion and non-oil sector formalisation programmes to increase IGR across the zone. Keywords: internally generated revenue, South South states, panel data, fiscal statistics, revenue performance