Methodological Evaluation of Power-Distribution Equipment Systems in Uganda: A Difference-in-Differences Model for Yield Improvement

Power distribution networks in many developing nations are characterised by significant technical losses and unreliable supply. Systematic, quantitative evaluations of infrastructure interventions are scarce, limiting evidence-based investment and maintenance strategies. This study aims to develop and apply a robust quasi-experimental methodology to empirically measure the impact of upgraded distribution equipment on system yield within a national utility. A difference-in-differences (DiD) model was employed, analysing high-frequency operational data from treatment and control feeder groups before and after a large-scale equipment retrofit programme. The core model is Yᵢₜ = β₀ + β₁ Treatᵢ + β₂ Postₜ + δ (Treatᵢ · Postₜ) + εᵢₜ, where δ captures the causal effect. Inference is based on cluster-robust standard errors. The intervention caused a statistically significant increase in average daily yield of 8.7 percentage points (95% CI: 6.2 to 11.2). This improvement was primarily driven by a marked reduction in technical losses, with no evidence of heterogeneous effects across geographic regions. The applied DiD model provides a rigorous methodological framework for evaluating capital projects in power networks, confirming that targeted equipment upgrades can substantially enhance distribution efficiency. Utilities should adopt quasi-experimental evaluation designs for post-implementation project audits. Future investment planning should prioritise clusters of feeders with the highest pre-intervention loss profiles to maximise aggregate yield gains. power distribution, technical losses, causal inference, quasi-experimental design, infrastructure evaluation, developing economies This paper presents a novel application of the difference-in-differences model to isolate the causal impact of physical infrastructure upgrades on electrical distribution yield, providing a replicable analytical tool for engineers and planners.