Abstract
{ "background": "Industrial process safety in developing economies often relies on imported control system methodologies without localised validation. There is a critical gap in evidence regarding the comparative efficacy of these systems in mitigating operational risks within specific regional contexts, such as sub-Saharan Africa.", "purpose and objectives": "This study aimed to empirically compare the risk reduction performance of three prevalent process-control system methodologies—Failure Mode and Effects Analysis (FMEA), Hazard and Operability Study (HAZOP), and a hybrid Bow-Tie approach—within the industrial landscape of Rwanda.", "methodology": "A quasi-experimental design was employed, implementing each methodology across matched cohorts of manufacturing and processing plants. Risk reduction was quantified using a composite safety performance index (SPI). The primary analysis utilised a fixed-effects panel model: $\\Delta SPI{it} = \\beta0 + \\beta1 Methodology{it} + \\gamma X{it} + \\alphai + \\epsilon{it}$, where $\\alphai$ denotes plant-level fixed effects. Robust standard errors were clustered at the plant level.", "findings": "The hybrid Bow-Tie methodology yielded a significantly greater mean improvement in SPI (22.4%, 95% CI [18.7, 26.1]) compared to HAZOP (14.1%) and FMEA (9.8%). The treatment effect for Bow-Tie remained statistically significant (p < 0.01) after controlling for plant size and maintenance expenditure.", "conclusion": "The findings demonstrate that the choice of process-control methodology has a substantial, measurable impact on industrial risk reduction outcomes in this context. The structured, barrier-based approach of the hybrid Bow-Tie method proved most effective.", "recommendations": "Industry regulators should consider promoting barrier-based methodologies in safety guidelines. Plant engineers are advised to integrate Bow-Tie analysis into their safety management systems, supplemented by foundational HAZOP studies for process understanding.", "key words": "process safety, risk assessment, quasi-experiment,