{ "background": "Process-control systems in industrial and infrastructure projects are critical for operational efficiency and safety. In many developing contexts, systematic evaluation of their reliability is hindered by a lack of controlled field data and standardised diagnostic methodologies, leading to unplanned downtime and maintenance costs.", "purpose and objectives": "This working paper aims to develop and apply a quasi-experimental methodological framework for the empirical evaluation and reliability diagnostics of process-control systems. The primary objective is to quantify system failure rates and identify key diagnostic parameters under operational field conditions.", "methodology": "A quasi-experimental design was implemented, comparing system performance across matched treatment and control groups of installed systems. Reliability was modelled using a Weibull survival analysis, specified as $\\lambda(t|\\mathbf{x}) = \\frac{\\beta}{\\alpha} \\left( \\frac{t}{\\alpha} \\right)^{\\beta-1} \\exp(\\mathbf{x}^\\top \\gamma)$, where $\\lambda$ is the hazard rate, $t$ is time, and $\\mathbf{x}$ is a vector of covariates. Diagnostics included signal analysis and fault-tree assessments. Robust standard errors were calculated to account for heteroskedasticity.", "findings": "The analysis indicates a significant directional increase in the hazard rate for systems operating beyond specified electrical tolerance bands. A key finding is that approximately 40% of observed system faults were attributable to inconsistencies in signal integrity from primary sensors. The estimated shape parameter $\\beta$ was significantly greater than 1 (95% CI: 1.3 to 1.9), indicating an increasing failure rate over time.", "conclusion": "The proposed quasi-experimental framework provides a viable method for field-based reliability assessment where fully randomised trials are impractical. The results demonstrate that sensor signal degradation is a predominant, quantifiable failure pathway for the systems studied.", "recommendations": "Implement routine diagnostic protocols focused on signal integrity verification. Design specifications for new installations should include wider electrical tolerances and enhanced signal conditioning.