{ "background": "Municipal infrastructure asset management in developing nations faces significant challenges in evaluating the efficacy of different management systems. In Nigeria, the adoption of modern asset management systems has been inconsistent, creating a need for robust methodological frameworks to analyse their impact and adoption drivers.", "purpose and objectives": "This study aims to conduct a methodological evaluation of different municipal infrastructure asset management systems. Its primary objective is to develop and apply a difference-in-differences (DiD) model to quantify the causal effect of policy interventions on the adoption rates of these systems across Nigerian municipalities.", "methodology": "A comparative longitudinal study design was employed, analysing panel data from a sample of municipalities. The core analytical framework is a two-way fixed effects DiD model: $Y{it} = \\alpha + \\beta (Treati \\times Postt) + \\gammai + \\deltat + \\epsilon{it}$, where $Y_{it}$ is the adoption rate. Inference is based on cluster-robust standard errors at the municipal level.", "findings": "The analysis indicates a statistically significant positive treatment effect from targeted capacity-building interventions. Municipalities receiving the intervention showed a 22 percentage point greater increase in adoption rates compared to the control group (95% CI: 15 to 29). The model's parallel trends assumption was validated using pre-intervention data.", "conclusion": "The DiD model provides a rigorous methodological framework for evaluating infrastructure management policies in this context. The results demonstrate that specific interventions can substantially accelerate the uptake of modern asset management systems.", "recommendations": "Policy makers should prioritise integrated capacity-building programmes that combine technical training with institutional support. Future research should apply this model to longitudinal data on asset condition and service delivery outcomes.", "key words": "asset management, difference-in-differences, infrastructure, municipal engineering, policy evaluation, adoption rate", "contribution statement": "This paper provides a novel application of the DiD econometric model to the field of civil infrastructure asset management,