Input Utilization and Agricultural Productivity: Panel Evidence from Tanzania, Kenya, Uganda, and Rwanda

Agriculture is central to livelihoods in East Africa, employing nearly 60% of the labor force, yet productivity growth has remained modest. This study examines the determinants of agricultural productivity in Tanzania, Kenya, Uganda, and Rwanda between 2000 and 2023. Using panel data from the World Development Indicators and a fixed effects regression framework, agricultural value added per worker is modeled as a function of fertilizer consumption, arable land use, rural population share, and GDP growth. Diagnostic tests confirmed no multicollinearity, while het-eroskedasticity and autocorrelation were detected and corrected with clustered standard errors. Panel unit root tests revealed mixed integration orders, with fertilizer consumption stationary af-ter first differencing. Robustness checks, including specifications with lagged fertilizer consump-tion, robust standard errors, and random effects, demonstrated coefficient stability, and residual cross section dependence tests indicated independence across countries. Results show that ferti-lizer consumption (β = 0.1085, p < 0.01), arable land use (β = 0.7648, p < 0.01), and rural popula-tion share (β = 1.4112, p < 0.01) significantly enhance productivity, while GDP growth is statisti-cally insignificant (β = 0.0013, p > 0.05). These findings suggest that productivity improvements in East Africa are driven primarily by input intensification and labor utilization rather than macroeco-nomic expansion. The study concludes that policies expanding fertilizer access, promoting sus-tainable land management, and enhancing rural labor efficiency are essential to support agricul-tural transformation and strengthen food security