"background": "The expansion and modernisation of power distribution infrastructure in sub-Saharan Africa requires robust, evidence-based methods for evaluating the cost-effectiveness of competing equipment systems. Current evaluation practices often lack rigorous counterfactual analysis, leading to potential misallocation of capital. ", "purpose and objectives": "This study develops and applies a quasi-experimental difference-in-differences (DiD) model to empirically evaluate the comparative cost-effectiveness of two prevalent medium-voltage distribution equipment systems deployed across multiple regions. ", "methodology": "A panel dataset of operational and capital expenditure for 42 distribution feeders over multiple years was constructed. The causal effect of equipment type on total cost was estimated using a two-way fixed effects DiD model: Y{it = \ + \ (Treati \ Postt) + \ + \ +, where robust standard errors were clustered at the feeder level. Cost-effectiveness was measured via the net present value of differential life-cycle costs. ", "findings": "The insulated conductor system demonstrated a statistically significant reduction in average annual operational expenditure of approximately 17% (95% CI: 12% to 22%) compared to the bare conductor alternative, after controlling for feeder length and customer density. This operational saving offset its higher initial capital outlay within the evaluated period. ", "conclusion": "The applied DiD model provides a rigorous, transferable framework for infrastructure investment appraisal, moving beyond descriptive comparison. The results indicate that the higher upfront cost of insulated systems can be economically justified through substantial operational savings. ", "recommendations": "Utilities and regulators should adopt quasi-experimental evaluation methods for major infrastructure programmes. Procurement policies should consider life-cycle cost models informed by causal analysis, rather than relying solely on initial capital cost. ", "key words": "difference-in-differences, cost-effectiveness, power distribution, infrastructure evaluation, quasi-experimental design, Kenya", "contribution statement": "This paper provides the first application of a difference-in-differences model to
Jeffrey Brown (Sun,) studied this question.