Growth, Macroeconomic Fundamentals and Institutional Heterogeneity in ECOWAS, 1970–2025

Regional integration in West Africa has advanced alongside persistent macroeconomic heterogeneity, so membership in ECOWAS cannot be treated as evidence of convergent adjustment. This article examines whether differences in growth performance across ECOWAS economies are better explained by regional membership itself or by the interaction of macroeconomic fundamentals and institutional chronology. Using an annual panel for 1970–2025 assembled by harmonizing World Bank World Development Indicators and IMF World Economic Outlook series, the article codes ECOWAS membership separately from UEMOA and CFA status, the Mauritanian withdrawal effective in 2000, and the AES withdrawals effective in 2025. The empirical strategy follows a sequenced estimator ladder: fixedeffects and two-way fixed-effects models identify within-country associations, dynamic-panel specifications assess persistence and partial endogeneity, and panel error-correction models in the ARDL family are used to examine long-run relationships. The core panel estimates indicate that investment is the most stable correlate of real GDP per capita growth. Inflation carries a negative average association with growth, but this effect weakens once common time shocks are absorbed. Trade openness remains positive but sample-sensitive and does not provide a stable anchor for inference. Break specifications point to an initial negative post-2025 shift for AES countries relative to the rest of ECOWAS, whereas the 2000 Mauritanian break is mature enough to sustain post-break analysis. The article contributes a replicable regional macro panel, explicit institutional coding, and a disciplined estimator hierarchy for analysing macroeconomic heterogeneity in West Africa.