{ "background": "Municipal infrastructure asset management systems (MIAMS) in South Africa are widely acknowledged as underperforming, leading to service delivery failures and financial inefficiencies. However, robust empirical evidence quantifying the impact of systematic interventions on MIAMS efficiency is scarce, hindering evidence-based policy and investment.", "purpose and objectives": "This study aimed to develop and apply a quasi-experimental methodology to measure causal efficiency gains from a structured intervention programme implemented across multiple municipalities. The primary objective was to estimate the average treatment effect on the treated (ATT) for key asset management performance indicators.", "methodology": "A difference-in-differences (DiD) design was employed, comparing treated municipalities (n=15) with a matched control group (n=15) over a multi-year period. The intervention comprised standardised asset registers, condition assessment protocols, and lifecycle planning tools. The core statistical model was $Y{it} = \\beta0 + \\beta1 \\text{Treat}i + \\beta2 \\text{Post}t + \\delta (\\text{Treat}i \\times \\text{Post}t) + \\epsilon_{it}$, where $\\delta$ is the ATT. Inference was based on cluster-robust standard errors at the municipal level.", "findings": "The intervention generated a statistically significant positive ATT. Treated municipalities demonstrated a 22% improvement in planned preventative maintenance compliance (95% CI: 15% to 29%) compared to the control group. Furthermore, a significant reduction in unplanned reactive maintenance expenditure was observed, with a coefficient of -0.18 (p < 0.01) in the DiD model.", "conclusion": "The quasi-experimental analysis provides causal evidence that standardised, systematic interventions can yield substantial efficiency improvements in municipal infrastructure management. The findings confirm that technical and procedural enhancements, when implemented cohesively, translate into measurable operational and financial gains.", "recommendations": "National and provincial governments should mandate the