"background": "Municipal infrastructure asset management systems (IAMs) in many African nations face chronic underfunding, yet rigorous evidence on the cost-effectiveness of different diagnostic and intervention approaches remains scarce. This creates significant challenges for engineering departments prioritising limited maintenance budgets. ", "purpose and objectives": "This working paper presents a methodological evaluation of a randomised field trial designed to measure the cost-effectiveness of diagnostic protocols for municipal IAMs. The primary objective is to determine which diagnostic approach yields the most reliable asset condition data per unit of expenditure. ", "methodology": "We conducted a clustered randomised field trial across multiple municipalities. Engineering teams were randomly assigned to implement one of three diagnostic protocols: a full physical survey, a risk-based sampling survey, or a community-participatory assessment. Cost data and diagnostic outputs were collected and analysed using a generalised linear model: \ (ij) = \0 + \1 + \ X{ij +, where i denotes assets, j protocols, and X a vector of controls. Inference is based on cluster-robust standard errors. ", "findings": "The risk-based sampling protocol generated asset condition data with 95% concordance to full survey benchmarks, but at 62% of the cost. The community-participatory method, while lowest cost, showed significantly higher measurement error for technical structural parameters. The estimated cost differential between the risk-based and full survey protocols was significant at the 5% level. ", "conclusion": "The trial demonstrates that methodological rigour in field diagnostics can be maintained while substantially reducing costs. Not all cost-saving diagnostic methods deliver data of sufficient quality for engineering decision-making. ", "recommendations": "Municipal engineering departments should adopt structured, risk-based sampling diagnostic protocols for routine asset condition assessments. Further trials are recommended to validate these protocols for specific infrastructure types, such as bridges and drainage networks. ", "key words
Ndiaye et al. (Sat,) studied this question.