{ "background": "The manufacturing sector in West Africa faces persistent challenges in productivity and cost efficiency. While technological upgrades are widely advocated, rigorous empirical evidence on the cost-effectiveness of different manufacturing systems in the region remains scarce, hindering informed investment and policy decisions.", "purpose and objectives": "This study aims to methodologically evaluate the impact of adopting advanced, integrated manufacturing systems on production costs within the Senegalese context. Its primary objective is to quantify the causal effect of system modernisation on cost per unit output, providing an evidence base for engineering and managerial decision-making.", "methodology": "A quasi-experimental difference-in-differences (DiD) model is employed, using panel data from a sample of manufacturing plants. The core estimating equation is $Y{it} = \\alpha + \\beta (Treati \\times Postt) + \\gammai + \\deltat + \\epsilon{it}$, where $Y_{it}$ is log cost per unit. The parallel trends assumption was tested and robust standard errors were clustered at the plant level to ensure valid inference.", "findings": "The analysis indicates a statistically significant reduction in average unit production costs for plants implementing the new systems, relative to the control group. The DiD estimator $\\beta$ was -0.15 (95% CI: -0.22, -0.08), implying an approximate 14% cost reduction attributable to the technological intervention.", "conclusion": "The adoption of integrated manufacturing systems demonstrates a significant and quantifiable cost advantage in the studied setting. The DiD approach provides a robust methodological framework for evaluating such engineering interventions in observational settings.", "recommendations": "Manufacturing firms should prioritise investments in systemic technological integration, supported by rigorous pre-implementation cost-benefit modelling. Policymakers are encouraged to develop targeted support mechanisms that mitigate upfront capital constraints for small and medium enterprises.", "key words": "difference-in-differences, cost-effectiveness, manufacturing systems, industrial engineering, Senegal, causal inference", "cont