"background": "Manufacturing systems in sub-Saharan Africa face persistent efficiency challenges, yet rigorous field-based diagnostic methodologies tailored to the regional context are scarce. Existing approaches often rely on observational data, lacking the causal rigour needed to isolate the impact of specific operational interventions. ", "purpose and objectives": "This case study evaluates a novel methodological framework for conducting randomised field trials (RFTs) to diagnose and measure efficiency gains within manufacturing plants. The primary objective was to assess the feasibility, implementation challenges, and analytical robustness of RFTs in this setting. ", "methodology": "A randomised field trial was implemented across a cohort of medium-scale manufacturing facilities. Plants were randomly assigned to treatment and control groups. The treatment involved a structured diagnostic audit followed by targeted process adjustments. Efficiency was measured via a throughput rate metric, analysed using a difference-in-differences model: Y{it = \0 + \1 + \2 + \ (\) + \₈ₓ, with inference based on cluster-robust standard errors. ", "findings": "The methodological evaluation revealed significant implementation hurdles, particularly in maintaining protocol adherence in the control group. The RFT design, however, yielded a precise estimate of the causal effect: the intervention increased average throughput by 14. 2 percentage points (95% CI: 8. 7, 19. 7). The primary theme from the process evaluation was the critical role of mid-level management engagement for trial fidelity. ", "conclusion": "Randomised field trials are a methodologically viable but practically demanding tool for engineering efficiency diagnostics in this context. They provide high-quality causal evidence but require substantial upfront investment in stakeholder alignment and monitoring systems. ", "recommendations": "Future applications should incorporate a pilot phase to refine data collection tools and establish stronger buy-in with plant floor supervisors. The diagnostic audit protocol should be adapted for faster deployment to
Kigozi et al. (Fri,) studied this question.