In Rwanda, manufacturing systems are pivotal for economic growth but often face inefficiencies in cost-effectiveness. A randomized controlled trial was implemented across five randomly selected manufacturing facilities. Data were collected through pre- and post-intervention surveys and financial records for analysis. The average reduction in production costs per unit output was found to be 15% with a standard error of ±2%, indicating statistically significant improvements (95% CI). This study demonstrates that targeted interventions can markedly enhance the cost-effectiveness of manufacturing operations, which is crucial for Rwanda's industrial development. Manufacturing companies in Rwanda should adopt cost-saving measures based on this trial and collaborate with research institutions to further optimise their processes. manufacturing systems, cost-effectiveness, randomized field trial, technological innovation The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.