This study examined the effect of public sector infrastructure investment on tax revenue in Nigeria, focusing on three critical infrastructure categories: education infrastructure, energy infrastructure, and health infrastructure The study adopted an ex-post facto research design grounded in positivist research philosophy, utilizing quarterly time series data spanning over three decades 1990Q to 2024Q quarterly, sourced from the Central Bank of Nigeria Statistical Bulletins, Federal Inland Revenue Service annual reports, and Federal Ministry of Finance appropriation documents. Prior to estimation, the Augmented Dickey-Fuller (ADF) unit root test was conducted to examine the stationarity properties of all variables. The results confirmed that all variables tax revenue, education infrastructure, energy infrastructure, and health infrastructure were stationary at level, denoted as I(0), with ADF statistics exceeding critical values at all conventional significance levels. This uniform stationarity at level eliminated concerns of spurious regression and negated the need for cointegration-based approaches, thereby justifying the adoption of the Ordinary Least Squares (OLS) regression technique to estimate the effects of infrastructure investment proxies on non-oil tax revenue as a percentage of GDP. The empirical results indicate that education infrastructure has a positive and statistically significant effect on tax revenue, while energy infrastructure also demonstrates a positive effect on tax revenue. Conversely, health infrastructure exhibited a negative but statistically insignificant effect. The study concluded that public sector infrastructure investment constitutes a significant determinant of tax revenue mobilization in Nigeria, with energy infrastructure emerging as the most fiscally productive investment category. Policy recommendations include prioritizing energy infrastructure investment for maximum fiscal returns, sustaining education infrastructure spending for human capital development, reforming health infrastructure investment strategy to address implementation challenges, and strengthening tax administration to capture infrastructure-induced economic growth.
Mohammed et al. (Sat,) studied this question.