MACROECONOMIC DETERMINANTS OF LIFE EXPECTANCY IN NIGERIA: THE ROLE OF INSTITUTIONAL QUALITY

This study examines the macroeconomic determinants of life expectancy in Nigeria, focusing on institutional quality alongside GDP per capita, inflation, and interest rate, using annual data spanning 1996 to 2025 sourced from the World Development Indicators and Worldwide Governance Indicators. The Augmented Dickey-Fuller confirmed a mixed order of integration, with institutional quality stationary at level, I(0), and all other variables stationary at first difference, I(1), justifying the Autoregressive Distributed Lag (ARDL) bounds testing approach. The bounds test (F = 3.8108) exceeded the Pesaran et al. (2001) upper bound at 5% (3.49), confirming long-run cointegration. No individual regressor emerged as a significant long-run determinant: GDP per capita (-0.4553), inflation (-0.1202), interest rate (-0.0200), and institutional quality (0.0089). In the short run, however, GDP per capita, inflation, and institutional quality were statistically significant, while interest rate was not; the error correction term (-0.2364) was highly significant, confirming a 23.6% speed of adjustment toward long-run equilibrium. Toda-Yamamoto causality tests revealed significant bidirectional causality between GDP per capita and life expectancy, and between institutional quality and life expectancy. The study concludes that while short-run and causal linkages exist among these variables, no single macroeconomic factor or institutional quality can be isolated as a robust, significant long-run driver of life expectancy in Nigeria and recommends that strategic investments in healthcare remain theoretically important foundational drivers of sustainable development.