Journal Design Engineering Masthead
African Civil Engineering Journal | 24 January 2009

A Randomised Field Trial for the Cost-Effectiveness Diagnostics of Process-Control Systems in Rwanda

J, e, a, n, d, e, D, i, e, u, U, w, i, m, a, n, a, ,, C, l, a, u, d, i, n, e, M, u, t, e, s, i
Cost-EffectivenessProcess-ControlRandomised TrialEngineering Policy
Intervention group showed a mean efficiency improvement of 18.7% relative to controls.
A 10% reduction in system cost increased probability of cost-effectiveness by 32 percentage points.
Cost-effectiveness was highly variable, challenging assumptions of universal viability.
Findings question policy mandates for adoption without targeted subsidies in low-resource contexts.

Abstract

{ "background": "Process-control systems are critical for infrastructure efficiency and safety, yet their adoption in resource-constrained settings is often hindered by a lack of robust, context-specific data on their economic viability. Evidence from sub-Saharan Africa on the cost-effectiveness of such engineering interventions remains particularly scarce.", "purpose and objectives": "This policy analysis aims to provide a methodological evaluation of process-control systems via a randomised field trial, establishing a framework for determining their cost-effectiveness in a low-resource context. The primary objective was to quantify the incremental cost per unit of efficiency gain.", "methodology": "A randomised controlled trial was conducted, assigning manufacturing and water treatment facilities to either an intervention group (installation of new process-control systems) or a control group (existing practices). Cost data and engineering performance metrics were collected over an operational period. Cost-effectiveness was evaluated using a generalised linear model: $\\log(\\text{Efficiency}{it}) = \\beta0 + \\beta1 \\text{Treatment}{i} + \\beta2 \\text{Cost}{it} + \\epsilon_{it}$, with inference based on cluster-robust standard errors.", "findings": "The intervention group showed a mean efficiency improvement of 18.7% (95% CI: 14.2, 23.1) relative to controls. However, the incremental cost-effectiveness ratio was highly variable, with the model indicating that a 10% reduction in system cost would increase the probability of being cost-effective by 32 percentage points, holding performance constant.", "conclusion": "While process-control systems can deliver significant engineering performance gains, their cost-effectiveness is not assured and is highly sensitive to initial capital expenditure. Policy mandates for adoption without targeted subsidies may lead to inefficient resource allocation.", "recommendations": "Policy should prioritise phased implementation supported by targeted capital subsidies for proven systems. National engineering standards should incorporate cost-effectiveness diagnostics based on localised operational data. Further trials should investigate lifecycle costing.", "key words": "cost-effectiveness analysis