Agricultural total factor productivity growth in Southern Africa: decomposition, determinants, and pathways to food security

Agricultural total factor productivity (TFP) is a central pathway for expanding food production in developing countries without proportional input growth. This study builds a balanced panel of ten Southern African Development Community (SADC) countries over 2000–2025 and applies the Tornqvist index to measure TFP growth, decompose it into technical efficiency change (TEC) and technological change (TC), and identify its determinants, with robustness established under weather-adjusted series and three alternative frontier definitions. Findings reveal that regional TFP grew 0.60% per annum, driven entirely by efficiency convergence (TEC = 0.99%); the measured frontier declined 0.39% annually, a contraction traceable to the cyclical productivity of Angola’s post-conflict reconstruction as opposed to regional technological stagnation, since the frontier advances under robustness-based definitions. Regional TFP and undernourishment moved inversely over 2000–2020 (r = −0.89, p < 0.001), confirming a food security channel, while growth accounting shows most economies remaining input-extensive, with TFP below 40% of output growth in seven of the ten countries. Government investment, income per capita, and agricultural value added were the most consistent correlates of productivity. The implication is that progress is real but insufficient, and sustained investment in agricultural research, development, and technology transfer is the binding requirement for productivity-led food security in southern Africa.