Abstract

Statistical modeling of demographic dynamics under external shocks represents a critical and underexplored area in applied statistics. Among such shocks, armed conflict stands out not only as a humanitarian crisis but also as a catalyst of demographic transformation. This study investigates how conflict influences age dependency ratios-young, old, total- in Nigeria using annual time-series data from 1960 to 2023. A Generalized Linear Model with Heteroskedasticity and Autocorrelation Consistent (HAC) errors is employed, complemented by Bai-Perron structural break tests. This combined approach was used to estimate the effects of conflict through three demographic pathways: selective mortality, forced displacement, and fertility, while accounting for autocorrelation, non-constant variance, regime shifts and structural changes over time. The results reveal statistically significant breakpoints in total and elderly dependency ratios during major conflict and political transition periods, indicating long-term demographic restructuring. Fertility rate shows the strongest effect, significantly increasing both total (0.4398, p < 0.01) and old-age (0.3306, p < 0.01) dependency ratios. Displacement also raises total (0.002, p < 0.05) dependency while reducing youth (-0.0008, p < 0.05) dependency, reflecting asymmetric population redistribution. Conflict-related mortality, though a humanitarian concern, does not significantly affect national-level demographic indicators, supporting the view that its demographic impact is diffuse in large populations. In conclusion, while Malthusian and Youth Bulge theories often frame demographic pressures as triggers of conflict, these findings provide empirical evidence that conflict itself can drive demographic transitions. The study advances the mathematical modeling of population change in fragile settings and offer policy-relevant insights for managing demographic risks in post-conflict development.