{ "background": "The integration of advanced process-control systems into industrial infrastructure is a key strategy for enhancing operational efficiency in developing economies. However, rigorous quantitative evaluations of their impact within the African context, particularly using causal inference methods, are scarce.", "purpose and objectives": "This study aims to empirically quantify the causal effect of modern process-control system retrofits on the operational efficiency of industrial plants. The primary objective is to isolate and measure efficiency gains attributable to the technological intervention, controlling for external temporal trends.", "methodology": "A quasi-experimental difference-in-differences (DiD) model was employed, analysing panel data from treatment and control groups of industrial facilities. The core estimating equation is $Y{it} = \\beta0 + \\beta1 \\text{Treat}i + \\beta2 \\text{Post}t + \\delta (\\text{Treat}i \\cdot \\text{Post}t) + \\epsilon_{it}$, where $\\delta$ captures the causal effect. Inference is based on cluster-robust standard errors at the facility level.", "findings": "The analysis reveals a statistically significant positive treatment effect. Plants retrofitted with modern process-control systems demonstrated a mean efficiency gain of 18.7% (95% CI: 14.2% to 23.2%) relative to the control group, with the effect being robust across multiple model specifications.", "conclusion": "The application of a DiD framework provides robust evidence that targeted upgrades to process-control infrastructure yield substantial and measurable improvements in industrial operational efficiency.", "recommendations": "Industrial policy and infrastructure investment strategies should prioritise funding for process-control modernisation programmes. Further research should investigate the specific system architectures that maximise these efficiency gains.", "key words": "process control, industrial efficiency, difference-in-differences, causal inference, infrastructure retrofitting", "contribution statement": "This paper provides the first application of a difference-in-differences econometric model to isolate the