A Randomised Field Trial for the Cost-Effectiveness Diagnostics of Municipal Infrastructure Asset Management Systems in Rwanda

{ "background": "Municipal infrastructure asset management systems (IAMs) are critical for sustainable development, yet evidence of their cost-effectiveness in low-resource settings remains sparse. Evaluations often lack rigorous experimental designs, limiting actionable insights for policymakers and engineers.", "purpose and objectives": "This study aimed to conduct a methodologically robust evaluation of the cost-effectiveness of different IAM diagnostic approaches implemented by municipal authorities. The primary objective was to quantify the incremental cost per unit improvement in asset condition score attributable to a structured diagnostic protocol.", "methodology": "A randomised field trial was conducted across multiple municipalities. Authorities were randomly assigned to either a treatment group, implementing a new structured diagnostic protocol, or a control group, using existing practice. Cost data and asset condition indices were collected over a standardised period. Cost-effectiveness was analysed using a generalised linear model: log(-Effectiveness Ratioi) = \β0 + \β1 i + Ξ\\β + \, where is a vector of covariates including baseline infrastructure quality. Inference was based on robust standard errors.", "findings": "The structured diagnostic protocol generated a statistically significant improvement in asset condition scores. However, it increased average management costs by approximately 32% compared to existing practice. The incremental cost-effectiveness ratio was estimated at RWF 1.2 million per 0.1 unit improvement in the condition index (95% CI: RWF 0.9m to RWF 1.6m).", "conclusion": "While the structured diagnostic protocol enhances technical assessment quality, its substantial cost increment challenges financial sustainability in typical municipal budgets. The value hinges on the long-term asset lifecycle savings, which were not captured in this trial's timeframe.", "recommendations": "Municipalities should adopt elements of the structured protocol selectively, focusing on high-criticality assets. National infrastructure agencies should consider targeted subsidies for diagnostic